1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 49 #include <dlfcn.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include "debug.h" 60 #include "rtld.h" 61 #include "libmap.h" 62 #include "rtld_tls.h" 63 #include "rtld_printf.h" 64 #include "notes.h" 65 66 #ifndef COMPAT_32BIT 67 #define PATH_RTLD "/libexec/ld-elf.so.1" 68 #else 69 #define PATH_RTLD "/libexec/ld-elf32.so.1" 70 #endif 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void die(void) __dead2; 81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **); 83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 88 int lo_flags, int mode); 89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91 static bool donelist_check(DoneList *, const Obj_Entry *); 92 static void errmsg_restore(char *); 93 static char *errmsg_save(void); 94 static void *fill_search_info(const char *, size_t, void *); 95 static char *find_library(const char *, const Obj_Entry *); 96 static const char *gethints(void); 97 static void init_dag(Obj_Entry *); 98 static void init_rtld(caddr_t, Elf_Auxinfo **); 99 static void initlist_add_neededs(Needed_Entry *, Objlist *); 100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 101 static void linkmap_add(Obj_Entry *); 102 static void linkmap_delete(Obj_Entry *); 103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 104 static void unload_filtees(Obj_Entry *); 105 static int load_needed_objects(Obj_Entry *, int); 106 static int load_preload_objects(void); 107 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 108 static void map_stacks_exec(RtldLockState *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 111 static void objlist_call_init(Objlist *, RtldLockState *); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 120 RtldLockState *); 121 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 122 int flags, RtldLockState *lockstate); 123 static int rtld_dirname(const char *, char *); 124 static int rtld_dirname_abs(const char *, char *); 125 static void *rtld_dlopen(const char *name, int fd, int mode); 126 static void rtld_exit(void); 127 static char *search_library_path(const char *, const char *); 128 static const void **get_program_var_addr(const char *, RtldLockState *); 129 static void set_program_var(const char *, const void *); 130 static int symlook_default(SymLook *, const Obj_Entry *refobj); 131 static int symlook_global(SymLook *, DoneList *); 132 static void symlook_init_from_req(SymLook *, const SymLook *); 133 static int symlook_list(SymLook *, const Objlist *, DoneList *); 134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 135 static int symlook_obj1(SymLook *, const Obj_Entry *); 136 static void trace_loaded_objects(Obj_Entry *); 137 static void unlink_object(Obj_Entry *); 138 static void unload_object(Obj_Entry *); 139 static void unref_dag(Obj_Entry *); 140 static void ref_dag(Obj_Entry *); 141 static int origin_subst_one(char **, const char *, const char *, 142 const char *, char *); 143 static char *origin_subst(const char *, const char *); 144 static void preinit_main(void); 145 static int rtld_verify_versions(const Objlist *); 146 static int rtld_verify_object_versions(Obj_Entry *); 147 static void object_add_name(Obj_Entry *, const char *); 148 static int object_match_name(const Obj_Entry *, const char *); 149 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 150 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 151 struct dl_phdr_info *phdr_info); 152 153 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 154 155 /* 156 * Data declarations. 157 */ 158 static char *error_message; /* Message for dlerror(), or NULL */ 159 struct r_debug r_debug; /* for GDB; */ 160 static bool libmap_disable; /* Disable libmap */ 161 static bool ld_loadfltr; /* Immediate filters processing */ 162 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 163 static bool trust; /* False for setuid and setgid programs */ 164 static bool dangerous_ld_env; /* True if environment variables have been 165 used to affect the libraries loaded */ 166 static char *ld_bind_now; /* Environment variable for immediate binding */ 167 static char *ld_debug; /* Environment variable for debugging */ 168 static char *ld_library_path; /* Environment variable for search path */ 169 static char *ld_preload; /* Environment variable for libraries to 170 load first */ 171 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 172 static char *ld_tracing; /* Called from ldd to print libs */ 173 static char *ld_utrace; /* Use utrace() to log events. */ 174 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 175 static Obj_Entry **obj_tail; /* Link field of last object in list */ 176 static Obj_Entry *obj_main; /* The main program shared object */ 177 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 178 static unsigned int obj_count; /* Number of objects in obj_list */ 179 static unsigned int obj_loads; /* Number of objects in obj_list */ 180 181 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 182 STAILQ_HEAD_INITIALIZER(list_global); 183 static Objlist list_main = /* Objects loaded at program startup */ 184 STAILQ_HEAD_INITIALIZER(list_main); 185 static Objlist list_fini = /* Objects needing fini() calls */ 186 STAILQ_HEAD_INITIALIZER(list_fini); 187 188 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 189 190 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 191 192 extern Elf_Dyn _DYNAMIC; 193 #pragma weak _DYNAMIC 194 #ifndef RTLD_IS_DYNAMIC 195 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 196 #endif 197 198 int osreldate, pagesize; 199 200 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 201 202 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 203 static int max_stack_flags; 204 205 /* 206 * Global declarations normally provided by crt1. The dynamic linker is 207 * not built with crt1, so we have to provide them ourselves. 208 */ 209 char *__progname; 210 char **environ; 211 212 /* 213 * Used to pass argc, argv to init functions. 214 */ 215 int main_argc; 216 char **main_argv; 217 218 /* 219 * Globals to control TLS allocation. 220 */ 221 size_t tls_last_offset; /* Static TLS offset of last module */ 222 size_t tls_last_size; /* Static TLS size of last module */ 223 size_t tls_static_space; /* Static TLS space allocated */ 224 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 225 int tls_max_index = 1; /* Largest module index allocated */ 226 227 /* 228 * Fill in a DoneList with an allocation large enough to hold all of 229 * the currently-loaded objects. Keep this as a macro since it calls 230 * alloca and we want that to occur within the scope of the caller. 231 */ 232 #define donelist_init(dlp) \ 233 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 234 assert((dlp)->objs != NULL), \ 235 (dlp)->num_alloc = obj_count, \ 236 (dlp)->num_used = 0) 237 238 #define UTRACE_DLOPEN_START 1 239 #define UTRACE_DLOPEN_STOP 2 240 #define UTRACE_DLCLOSE_START 3 241 #define UTRACE_DLCLOSE_STOP 4 242 #define UTRACE_LOAD_OBJECT 5 243 #define UTRACE_UNLOAD_OBJECT 6 244 #define UTRACE_ADD_RUNDEP 7 245 #define UTRACE_PRELOAD_FINISHED 8 246 #define UTRACE_INIT_CALL 9 247 #define UTRACE_FINI_CALL 10 248 249 struct utrace_rtld { 250 char sig[4]; /* 'RTLD' */ 251 int event; 252 void *handle; 253 void *mapbase; /* Used for 'parent' and 'init/fini' */ 254 size_t mapsize; 255 int refcnt; /* Used for 'mode' */ 256 char name[MAXPATHLEN]; 257 }; 258 259 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 260 if (ld_utrace != NULL) \ 261 ld_utrace_log(e, h, mb, ms, r, n); \ 262 } while (0) 263 264 static void 265 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 266 int refcnt, const char *name) 267 { 268 struct utrace_rtld ut; 269 270 ut.sig[0] = 'R'; 271 ut.sig[1] = 'T'; 272 ut.sig[2] = 'L'; 273 ut.sig[3] = 'D'; 274 ut.event = event; 275 ut.handle = handle; 276 ut.mapbase = mapbase; 277 ut.mapsize = mapsize; 278 ut.refcnt = refcnt; 279 bzero(ut.name, sizeof(ut.name)); 280 if (name) 281 strlcpy(ut.name, name, sizeof(ut.name)); 282 utrace(&ut, sizeof(ut)); 283 } 284 285 /* 286 * Main entry point for dynamic linking. The first argument is the 287 * stack pointer. The stack is expected to be laid out as described 288 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 289 * Specifically, the stack pointer points to a word containing 290 * ARGC. Following that in the stack is a null-terminated sequence 291 * of pointers to argument strings. Then comes a null-terminated 292 * sequence of pointers to environment strings. Finally, there is a 293 * sequence of "auxiliary vector" entries. 294 * 295 * The second argument points to a place to store the dynamic linker's 296 * exit procedure pointer and the third to a place to store the main 297 * program's object. 298 * 299 * The return value is the main program's entry point. 300 */ 301 func_ptr_type 302 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 303 { 304 Elf_Auxinfo *aux_info[AT_COUNT]; 305 int i; 306 int argc; 307 char **argv; 308 char **env; 309 Elf_Auxinfo *aux; 310 Elf_Auxinfo *auxp; 311 const char *argv0; 312 Objlist_Entry *entry; 313 Obj_Entry *obj; 314 Obj_Entry **preload_tail; 315 Objlist initlist; 316 RtldLockState lockstate; 317 int mib[2]; 318 size_t len; 319 320 /* 321 * On entry, the dynamic linker itself has not been relocated yet. 322 * Be very careful not to reference any global data until after 323 * init_rtld has returned. It is OK to reference file-scope statics 324 * and string constants, and to call static and global functions. 325 */ 326 327 /* Find the auxiliary vector on the stack. */ 328 argc = *sp++; 329 argv = (char **) sp; 330 sp += argc + 1; /* Skip over arguments and NULL terminator */ 331 env = (char **) sp; 332 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 333 ; 334 aux = (Elf_Auxinfo *) sp; 335 336 /* Digest the auxiliary vector. */ 337 for (i = 0; i < AT_COUNT; i++) 338 aux_info[i] = NULL; 339 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 340 if (auxp->a_type < AT_COUNT) 341 aux_info[auxp->a_type] = auxp; 342 } 343 344 /* Initialize and relocate ourselves. */ 345 assert(aux_info[AT_BASE] != NULL); 346 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 347 348 __progname = obj_rtld.path; 349 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 350 environ = env; 351 main_argc = argc; 352 main_argv = argv; 353 354 if (aux_info[AT_CANARY] != NULL && 355 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 356 i = aux_info[AT_CANARYLEN]->a_un.a_val; 357 if (i > sizeof(__stack_chk_guard)) 358 i = sizeof(__stack_chk_guard); 359 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 360 } else { 361 mib[0] = CTL_KERN; 362 mib[1] = KERN_ARND; 363 364 len = sizeof(__stack_chk_guard); 365 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 366 len != sizeof(__stack_chk_guard)) { 367 /* If sysctl was unsuccessful, use the "terminator canary". */ 368 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 369 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 370 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 371 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 372 } 373 } 374 375 trust = !issetugid(); 376 377 ld_bind_now = getenv(LD_ "BIND_NOW"); 378 /* 379 * If the process is tainted, then we un-set the dangerous environment 380 * variables. The process will be marked as tainted until setuid(2) 381 * is called. If any child process calls setuid(2) we do not want any 382 * future processes to honor the potentially un-safe variables. 383 */ 384 if (!trust) { 385 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 386 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 387 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 388 unsetenv(LD_ "LOADFLTR")) { 389 _rtld_error("environment corrupt; aborting"); 390 die(); 391 } 392 } 393 ld_debug = getenv(LD_ "DEBUG"); 394 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 395 libmap_override = getenv(LD_ "LIBMAP"); 396 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 397 ld_preload = getenv(LD_ "PRELOAD"); 398 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 399 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 400 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 401 (ld_library_path != NULL) || (ld_preload != NULL) || 402 (ld_elf_hints_path != NULL) || ld_loadfltr; 403 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 404 ld_utrace = getenv(LD_ "UTRACE"); 405 406 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 407 ld_elf_hints_path = _PATH_ELF_HINTS; 408 409 if (ld_debug != NULL && *ld_debug != '\0') 410 debug = 1; 411 dbg("%s is initialized, base address = %p", __progname, 412 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 413 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 414 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 415 416 dbg("initializing thread locks"); 417 lockdflt_init(); 418 419 /* 420 * Load the main program, or process its program header if it is 421 * already loaded. 422 */ 423 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 424 int fd = aux_info[AT_EXECFD]->a_un.a_val; 425 dbg("loading main program"); 426 obj_main = map_object(fd, argv0, NULL); 427 close(fd); 428 if (obj_main == NULL) 429 die(); 430 max_stack_flags = obj->stack_flags; 431 } else { /* Main program already loaded. */ 432 const Elf_Phdr *phdr; 433 int phnum; 434 caddr_t entry; 435 436 dbg("processing main program's program header"); 437 assert(aux_info[AT_PHDR] != NULL); 438 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 439 assert(aux_info[AT_PHNUM] != NULL); 440 phnum = aux_info[AT_PHNUM]->a_un.a_val; 441 assert(aux_info[AT_PHENT] != NULL); 442 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 443 assert(aux_info[AT_ENTRY] != NULL); 444 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 445 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 446 die(); 447 } 448 449 if (aux_info[AT_EXECPATH] != 0) { 450 char *kexecpath; 451 char buf[MAXPATHLEN]; 452 453 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 454 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 455 if (kexecpath[0] == '/') 456 obj_main->path = kexecpath; 457 else if (getcwd(buf, sizeof(buf)) == NULL || 458 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 459 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 460 obj_main->path = xstrdup(argv0); 461 else 462 obj_main->path = xstrdup(buf); 463 } else { 464 dbg("No AT_EXECPATH"); 465 obj_main->path = xstrdup(argv0); 466 } 467 dbg("obj_main path %s", obj_main->path); 468 obj_main->mainprog = true; 469 470 if (aux_info[AT_STACKPROT] != NULL && 471 aux_info[AT_STACKPROT]->a_un.a_val != 0) 472 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 473 474 /* 475 * Get the actual dynamic linker pathname from the executable if 476 * possible. (It should always be possible.) That ensures that 477 * gdb will find the right dynamic linker even if a non-standard 478 * one is being used. 479 */ 480 if (obj_main->interp != NULL && 481 strcmp(obj_main->interp, obj_rtld.path) != 0) { 482 free(obj_rtld.path); 483 obj_rtld.path = xstrdup(obj_main->interp); 484 __progname = obj_rtld.path; 485 } 486 487 digest_dynamic(obj_main, 0); 488 489 linkmap_add(obj_main); 490 linkmap_add(&obj_rtld); 491 492 /* Link the main program into the list of objects. */ 493 *obj_tail = obj_main; 494 obj_tail = &obj_main->next; 495 obj_count++; 496 obj_loads++; 497 498 /* Initialize a fake symbol for resolving undefined weak references. */ 499 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 500 sym_zero.st_shndx = SHN_UNDEF; 501 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 502 503 if (!libmap_disable) 504 libmap_disable = (bool)lm_init(libmap_override); 505 506 dbg("loading LD_PRELOAD libraries"); 507 if (load_preload_objects() == -1) 508 die(); 509 preload_tail = obj_tail; 510 511 dbg("loading needed objects"); 512 if (load_needed_objects(obj_main, 0) == -1) 513 die(); 514 515 /* Make a list of all objects loaded at startup. */ 516 for (obj = obj_list; obj != NULL; obj = obj->next) { 517 objlist_push_tail(&list_main, obj); 518 obj->refcount++; 519 } 520 521 dbg("checking for required versions"); 522 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 523 die(); 524 525 if (ld_tracing) { /* We're done */ 526 trace_loaded_objects(obj_main); 527 exit(0); 528 } 529 530 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 531 dump_relocations(obj_main); 532 exit (0); 533 } 534 535 /* 536 * Processing tls relocations requires having the tls offsets 537 * initialized. Prepare offsets before starting initial 538 * relocation processing. 539 */ 540 dbg("initializing initial thread local storage offsets"); 541 STAILQ_FOREACH(entry, &list_main, link) { 542 /* 543 * Allocate all the initial objects out of the static TLS 544 * block even if they didn't ask for it. 545 */ 546 allocate_tls_offset(entry->obj); 547 } 548 549 if (relocate_objects(obj_main, 550 ld_bind_now != NULL && *ld_bind_now != '\0', 551 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 552 die(); 553 554 dbg("doing copy relocations"); 555 if (do_copy_relocations(obj_main) == -1) 556 die(); 557 558 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 559 dump_relocations(obj_main); 560 exit (0); 561 } 562 563 /* 564 * Setup TLS for main thread. This must be done after the 565 * relocations are processed, since tls initialization section 566 * might be the subject for relocations. 567 */ 568 dbg("initializing initial thread local storage"); 569 allocate_initial_tls(obj_list); 570 571 dbg("initializing key program variables"); 572 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 573 set_program_var("environ", env); 574 set_program_var("__elf_aux_vector", aux); 575 576 /* Make a list of init functions to call. */ 577 objlist_init(&initlist); 578 initlist_add_objects(obj_list, preload_tail, &initlist); 579 580 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 581 582 map_stacks_exec(NULL); 583 584 dbg("resolving ifuncs"); 585 if (resolve_objects_ifunc(obj_main, 586 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 587 NULL) == -1) 588 die(); 589 590 if (!obj_main->crt_no_init) { 591 /* 592 * Make sure we don't call the main program's init and fini 593 * functions for binaries linked with old crt1 which calls 594 * _init itself. 595 */ 596 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 597 obj_main->preinit_array = obj_main->init_array = 598 obj_main->fini_array = (Elf_Addr)NULL; 599 } 600 601 wlock_acquire(rtld_bind_lock, &lockstate); 602 if (obj_main->crt_no_init) 603 preinit_main(); 604 objlist_call_init(&initlist, &lockstate); 605 objlist_clear(&initlist); 606 dbg("loading filtees"); 607 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 608 if (ld_loadfltr || obj->z_loadfltr) 609 load_filtees(obj, 0, &lockstate); 610 } 611 lock_release(rtld_bind_lock, &lockstate); 612 613 dbg("transferring control to program entry point = %p", obj_main->entry); 614 615 /* Return the exit procedure and the program entry point. */ 616 *exit_proc = rtld_exit; 617 *objp = obj_main; 618 return (func_ptr_type) obj_main->entry; 619 } 620 621 void * 622 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 623 { 624 void *ptr; 625 Elf_Addr target; 626 627 ptr = (void *)make_function_pointer(def, obj); 628 target = ((Elf_Addr (*)(void))ptr)(); 629 return ((void *)target); 630 } 631 632 Elf_Addr 633 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 634 { 635 const Elf_Rel *rel; 636 const Elf_Sym *def; 637 const Obj_Entry *defobj; 638 Elf_Addr *where; 639 Elf_Addr target; 640 RtldLockState lockstate; 641 642 rlock_acquire(rtld_bind_lock, &lockstate); 643 if (sigsetjmp(lockstate.env, 0) != 0) 644 lock_upgrade(rtld_bind_lock, &lockstate); 645 if (obj->pltrel) 646 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 647 else 648 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 649 650 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 651 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 652 &lockstate); 653 if (def == NULL) 654 die(); 655 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 656 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 657 else 658 target = (Elf_Addr)(defobj->relocbase + def->st_value); 659 660 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 661 defobj->strtab + def->st_name, basename(obj->path), 662 (void *)target, basename(defobj->path)); 663 664 /* 665 * Write the new contents for the jmpslot. Note that depending on 666 * architecture, the value which we need to return back to the 667 * lazy binding trampoline may or may not be the target 668 * address. The value returned from reloc_jmpslot() is the value 669 * that the trampoline needs. 670 */ 671 target = reloc_jmpslot(where, target, defobj, obj, rel); 672 lock_release(rtld_bind_lock, &lockstate); 673 return target; 674 } 675 676 /* 677 * Error reporting function. Use it like printf. If formats the message 678 * into a buffer, and sets things up so that the next call to dlerror() 679 * will return the message. 680 */ 681 void 682 _rtld_error(const char *fmt, ...) 683 { 684 static char buf[512]; 685 va_list ap; 686 687 va_start(ap, fmt); 688 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 689 error_message = buf; 690 va_end(ap); 691 } 692 693 /* 694 * Return a dynamically-allocated copy of the current error message, if any. 695 */ 696 static char * 697 errmsg_save(void) 698 { 699 return error_message == NULL ? NULL : xstrdup(error_message); 700 } 701 702 /* 703 * Restore the current error message from a copy which was previously saved 704 * by errmsg_save(). The copy is freed. 705 */ 706 static void 707 errmsg_restore(char *saved_msg) 708 { 709 if (saved_msg == NULL) 710 error_message = NULL; 711 else { 712 _rtld_error("%s", saved_msg); 713 free(saved_msg); 714 } 715 } 716 717 static const char * 718 basename(const char *name) 719 { 720 const char *p = strrchr(name, '/'); 721 return p != NULL ? p + 1 : name; 722 } 723 724 static struct utsname uts; 725 726 static int 727 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 728 char *may_free) 729 { 730 const char *p, *p1; 731 char *res1; 732 int subst_len; 733 int kw_len; 734 735 res1 = *res = NULL; 736 p = real; 737 subst_len = kw_len = 0; 738 for (;;) { 739 p1 = strstr(p, kw); 740 if (p1 != NULL) { 741 if (subst_len == 0) { 742 subst_len = strlen(subst); 743 kw_len = strlen(kw); 744 } 745 if (*res == NULL) { 746 *res = xmalloc(PATH_MAX); 747 res1 = *res; 748 } 749 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 750 _rtld_error("Substitution of %s in %s cannot be performed", 751 kw, real); 752 if (may_free != NULL) 753 free(may_free); 754 free(res); 755 return (false); 756 } 757 memcpy(res1, p, p1 - p); 758 res1 += p1 - p; 759 memcpy(res1, subst, subst_len); 760 res1 += subst_len; 761 p = p1 + kw_len; 762 } else { 763 if (*res == NULL) { 764 if (may_free != NULL) 765 *res = may_free; 766 else 767 *res = xstrdup(real); 768 return (true); 769 } 770 *res1 = '\0'; 771 if (may_free != NULL) 772 free(may_free); 773 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 774 free(res); 775 return (false); 776 } 777 return (true); 778 } 779 } 780 } 781 782 static char * 783 origin_subst(const char *real, const char *origin_path) 784 { 785 char *res1, *res2, *res3, *res4; 786 787 if (uts.sysname[0] == '\0') { 788 if (uname(&uts) != 0) { 789 _rtld_error("utsname failed: %d", errno); 790 return (NULL); 791 } 792 } 793 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 794 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 795 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 796 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 797 return (NULL); 798 return (res4); 799 } 800 801 static void 802 die(void) 803 { 804 const char *msg = dlerror(); 805 806 if (msg == NULL) 807 msg = "Fatal error"; 808 rtld_fdputstr(STDERR_FILENO, msg); 809 rtld_fdputchar(STDERR_FILENO, '\n'); 810 _exit(1); 811 } 812 813 /* 814 * Process a shared object's DYNAMIC section, and save the important 815 * information in its Obj_Entry structure. 816 */ 817 static void 818 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 819 const Elf_Dyn **dyn_soname) 820 { 821 const Elf_Dyn *dynp; 822 Needed_Entry **needed_tail = &obj->needed; 823 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 824 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 825 int plttype = DT_REL; 826 827 *dyn_rpath = NULL; 828 *dyn_soname = NULL; 829 830 obj->bind_now = false; 831 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 832 switch (dynp->d_tag) { 833 834 case DT_REL: 835 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 836 break; 837 838 case DT_RELSZ: 839 obj->relsize = dynp->d_un.d_val; 840 break; 841 842 case DT_RELENT: 843 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 844 break; 845 846 case DT_JMPREL: 847 obj->pltrel = (const Elf_Rel *) 848 (obj->relocbase + dynp->d_un.d_ptr); 849 break; 850 851 case DT_PLTRELSZ: 852 obj->pltrelsize = dynp->d_un.d_val; 853 break; 854 855 case DT_RELA: 856 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 857 break; 858 859 case DT_RELASZ: 860 obj->relasize = dynp->d_un.d_val; 861 break; 862 863 case DT_RELAENT: 864 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 865 break; 866 867 case DT_PLTREL: 868 plttype = dynp->d_un.d_val; 869 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 870 break; 871 872 case DT_SYMTAB: 873 obj->symtab = (const Elf_Sym *) 874 (obj->relocbase + dynp->d_un.d_ptr); 875 break; 876 877 case DT_SYMENT: 878 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 879 break; 880 881 case DT_STRTAB: 882 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 883 break; 884 885 case DT_STRSZ: 886 obj->strsize = dynp->d_un.d_val; 887 break; 888 889 case DT_VERNEED: 890 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 891 dynp->d_un.d_val); 892 break; 893 894 case DT_VERNEEDNUM: 895 obj->verneednum = dynp->d_un.d_val; 896 break; 897 898 case DT_VERDEF: 899 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 900 dynp->d_un.d_val); 901 break; 902 903 case DT_VERDEFNUM: 904 obj->verdefnum = dynp->d_un.d_val; 905 break; 906 907 case DT_VERSYM: 908 obj->versyms = (const Elf_Versym *)(obj->relocbase + 909 dynp->d_un.d_val); 910 break; 911 912 case DT_HASH: 913 { 914 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 915 (obj->relocbase + dynp->d_un.d_ptr); 916 obj->nbuckets = hashtab[0]; 917 obj->nchains = hashtab[1]; 918 obj->buckets = hashtab + 2; 919 obj->chains = obj->buckets + obj->nbuckets; 920 } 921 break; 922 923 case DT_NEEDED: 924 if (!obj->rtld) { 925 Needed_Entry *nep = NEW(Needed_Entry); 926 nep->name = dynp->d_un.d_val; 927 nep->obj = NULL; 928 nep->next = NULL; 929 930 *needed_tail = nep; 931 needed_tail = &nep->next; 932 } 933 break; 934 935 case DT_FILTER: 936 if (!obj->rtld) { 937 Needed_Entry *nep = NEW(Needed_Entry); 938 nep->name = dynp->d_un.d_val; 939 nep->obj = NULL; 940 nep->next = NULL; 941 942 *needed_filtees_tail = nep; 943 needed_filtees_tail = &nep->next; 944 } 945 break; 946 947 case DT_AUXILIARY: 948 if (!obj->rtld) { 949 Needed_Entry *nep = NEW(Needed_Entry); 950 nep->name = dynp->d_un.d_val; 951 nep->obj = NULL; 952 nep->next = NULL; 953 954 *needed_aux_filtees_tail = nep; 955 needed_aux_filtees_tail = &nep->next; 956 } 957 break; 958 959 case DT_PLTGOT: 960 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 961 break; 962 963 case DT_TEXTREL: 964 obj->textrel = true; 965 break; 966 967 case DT_SYMBOLIC: 968 obj->symbolic = true; 969 break; 970 971 case DT_RPATH: 972 case DT_RUNPATH: /* XXX: process separately */ 973 /* 974 * We have to wait until later to process this, because we 975 * might not have gotten the address of the string table yet. 976 */ 977 *dyn_rpath = dynp; 978 break; 979 980 case DT_SONAME: 981 *dyn_soname = dynp; 982 break; 983 984 case DT_INIT: 985 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 986 break; 987 988 case DT_PREINIT_ARRAY: 989 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 990 break; 991 992 case DT_PREINIT_ARRAYSZ: 993 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 994 break; 995 996 case DT_INIT_ARRAY: 997 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 998 break; 999 1000 case DT_INIT_ARRAYSZ: 1001 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1002 break; 1003 1004 case DT_FINI: 1005 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1006 break; 1007 1008 case DT_FINI_ARRAY: 1009 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1010 break; 1011 1012 case DT_FINI_ARRAYSZ: 1013 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1014 break; 1015 1016 /* 1017 * Don't process DT_DEBUG on MIPS as the dynamic section 1018 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1019 */ 1020 1021 #ifndef __mips__ 1022 case DT_DEBUG: 1023 /* XXX - not implemented yet */ 1024 if (!early) 1025 dbg("Filling in DT_DEBUG entry"); 1026 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1027 break; 1028 #endif 1029 1030 case DT_FLAGS: 1031 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1032 obj->z_origin = true; 1033 if (dynp->d_un.d_val & DF_SYMBOLIC) 1034 obj->symbolic = true; 1035 if (dynp->d_un.d_val & DF_TEXTREL) 1036 obj->textrel = true; 1037 if (dynp->d_un.d_val & DF_BIND_NOW) 1038 obj->bind_now = true; 1039 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1040 ;*/ 1041 break; 1042 #ifdef __mips__ 1043 case DT_MIPS_LOCAL_GOTNO: 1044 obj->local_gotno = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_MIPS_SYMTABNO: 1048 obj->symtabno = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_MIPS_GOTSYM: 1052 obj->gotsym = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_MIPS_RLD_MAP: 1056 #ifdef notyet 1057 if (!early) 1058 dbg("Filling in DT_DEBUG entry"); 1059 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1060 #endif 1061 break; 1062 #endif 1063 1064 case DT_FLAGS_1: 1065 if (dynp->d_un.d_val & DF_1_NOOPEN) 1066 obj->z_noopen = true; 1067 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1068 obj->z_origin = true; 1069 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1070 XXX ;*/ 1071 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1072 obj->bind_now = true; 1073 if (dynp->d_un.d_val & DF_1_NODELETE) 1074 obj->z_nodelete = true; 1075 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1076 obj->z_loadfltr = true; 1077 break; 1078 1079 default: 1080 if (!early) { 1081 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1082 (long)dynp->d_tag); 1083 } 1084 break; 1085 } 1086 } 1087 1088 obj->traced = false; 1089 1090 if (plttype == DT_RELA) { 1091 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1092 obj->pltrel = NULL; 1093 obj->pltrelasize = obj->pltrelsize; 1094 obj->pltrelsize = 0; 1095 } 1096 } 1097 1098 static void 1099 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1100 const Elf_Dyn *dyn_soname) 1101 { 1102 1103 if (obj->z_origin && obj->origin_path == NULL) { 1104 obj->origin_path = xmalloc(PATH_MAX); 1105 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1106 die(); 1107 } 1108 1109 if (dyn_rpath != NULL) { 1110 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1111 if (obj->z_origin) 1112 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1113 } 1114 1115 if (dyn_soname != NULL) 1116 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1117 } 1118 1119 static void 1120 digest_dynamic(Obj_Entry *obj, int early) 1121 { 1122 const Elf_Dyn *dyn_rpath; 1123 const Elf_Dyn *dyn_soname; 1124 1125 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1126 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1127 } 1128 1129 /* 1130 * Process a shared object's program header. This is used only for the 1131 * main program, when the kernel has already loaded the main program 1132 * into memory before calling the dynamic linker. It creates and 1133 * returns an Obj_Entry structure. 1134 */ 1135 static Obj_Entry * 1136 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1137 { 1138 Obj_Entry *obj; 1139 const Elf_Phdr *phlimit = phdr + phnum; 1140 const Elf_Phdr *ph; 1141 Elf_Addr note_start, note_end; 1142 int nsegs = 0; 1143 1144 obj = obj_new(); 1145 for (ph = phdr; ph < phlimit; ph++) { 1146 if (ph->p_type != PT_PHDR) 1147 continue; 1148 1149 obj->phdr = phdr; 1150 obj->phsize = ph->p_memsz; 1151 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1152 break; 1153 } 1154 1155 obj->stack_flags = PF_X | PF_R | PF_W; 1156 1157 for (ph = phdr; ph < phlimit; ph++) { 1158 switch (ph->p_type) { 1159 1160 case PT_INTERP: 1161 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1162 break; 1163 1164 case PT_LOAD: 1165 if (nsegs == 0) { /* First load segment */ 1166 obj->vaddrbase = trunc_page(ph->p_vaddr); 1167 obj->mapbase = obj->vaddrbase + obj->relocbase; 1168 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1169 obj->vaddrbase; 1170 } else { /* Last load segment */ 1171 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1172 obj->vaddrbase; 1173 } 1174 nsegs++; 1175 break; 1176 1177 case PT_DYNAMIC: 1178 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1179 break; 1180 1181 case PT_TLS: 1182 obj->tlsindex = 1; 1183 obj->tlssize = ph->p_memsz; 1184 obj->tlsalign = ph->p_align; 1185 obj->tlsinitsize = ph->p_filesz; 1186 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1187 break; 1188 1189 case PT_GNU_STACK: 1190 obj->stack_flags = ph->p_flags; 1191 break; 1192 1193 case PT_GNU_RELRO: 1194 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1195 obj->relro_size = round_page(ph->p_memsz); 1196 break; 1197 1198 case PT_NOTE: 1199 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1200 note_end = note_start + ph->p_filesz; 1201 digest_notes(obj, note_start, note_end); 1202 break; 1203 } 1204 } 1205 if (nsegs < 1) { 1206 _rtld_error("%s: too few PT_LOAD segments", path); 1207 return NULL; 1208 } 1209 1210 obj->entry = entry; 1211 return obj; 1212 } 1213 1214 void 1215 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1216 { 1217 const Elf_Note *note; 1218 const char *note_name; 1219 uintptr_t p; 1220 1221 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1222 note = (const Elf_Note *)((const char *)(note + 1) + 1223 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1224 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1225 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1226 note->n_descsz != sizeof(int32_t)) 1227 continue; 1228 if (note->n_type != ABI_NOTETYPE && 1229 note->n_type != CRT_NOINIT_NOTETYPE) 1230 continue; 1231 note_name = (const char *)(note + 1); 1232 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1233 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1234 continue; 1235 switch (note->n_type) { 1236 case ABI_NOTETYPE: 1237 /* FreeBSD osrel note */ 1238 p = (uintptr_t)(note + 1); 1239 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1240 obj->osrel = *(const int32_t *)(p); 1241 dbg("note osrel %d", obj->osrel); 1242 break; 1243 case CRT_NOINIT_NOTETYPE: 1244 /* FreeBSD 'crt does not call init' note */ 1245 obj->crt_no_init = true; 1246 dbg("note crt_no_init"); 1247 break; 1248 } 1249 } 1250 } 1251 1252 static Obj_Entry * 1253 dlcheck(void *handle) 1254 { 1255 Obj_Entry *obj; 1256 1257 for (obj = obj_list; obj != NULL; obj = obj->next) 1258 if (obj == (Obj_Entry *) handle) 1259 break; 1260 1261 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1262 _rtld_error("Invalid shared object handle %p", handle); 1263 return NULL; 1264 } 1265 return obj; 1266 } 1267 1268 /* 1269 * If the given object is already in the donelist, return true. Otherwise 1270 * add the object to the list and return false. 1271 */ 1272 static bool 1273 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1274 { 1275 unsigned int i; 1276 1277 for (i = 0; i < dlp->num_used; i++) 1278 if (dlp->objs[i] == obj) 1279 return true; 1280 /* 1281 * Our donelist allocation should always be sufficient. But if 1282 * our threads locking isn't working properly, more shared objects 1283 * could have been loaded since we allocated the list. That should 1284 * never happen, but we'll handle it properly just in case it does. 1285 */ 1286 if (dlp->num_used < dlp->num_alloc) 1287 dlp->objs[dlp->num_used++] = obj; 1288 return false; 1289 } 1290 1291 /* 1292 * Hash function for symbol table lookup. Don't even think about changing 1293 * this. It is specified by the System V ABI. 1294 */ 1295 unsigned long 1296 elf_hash(const char *name) 1297 { 1298 const unsigned char *p = (const unsigned char *) name; 1299 unsigned long h = 0; 1300 unsigned long g; 1301 1302 while (*p != '\0') { 1303 h = (h << 4) + *p++; 1304 if ((g = h & 0xf0000000) != 0) 1305 h ^= g >> 24; 1306 h &= ~g; 1307 } 1308 return h; 1309 } 1310 1311 /* 1312 * Find the library with the given name, and return its full pathname. 1313 * The returned string is dynamically allocated. Generates an error 1314 * message and returns NULL if the library cannot be found. 1315 * 1316 * If the second argument is non-NULL, then it refers to an already- 1317 * loaded shared object, whose library search path will be searched. 1318 * 1319 * The search order is: 1320 * LD_LIBRARY_PATH 1321 * rpath in the referencing file 1322 * ldconfig hints 1323 * /lib:/usr/lib 1324 */ 1325 static char * 1326 find_library(const char *xname, const Obj_Entry *refobj) 1327 { 1328 char *pathname; 1329 char *name; 1330 1331 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1332 if (xname[0] != '/' && !trust) { 1333 _rtld_error("Absolute pathname required for shared object \"%s\"", 1334 xname); 1335 return NULL; 1336 } 1337 if (refobj != NULL && refobj->z_origin) 1338 return origin_subst(xname, refobj->origin_path); 1339 else 1340 return xstrdup(xname); 1341 } 1342 1343 if (libmap_disable || (refobj == NULL) || 1344 (name = lm_find(refobj->path, xname)) == NULL) 1345 name = (char *)xname; 1346 1347 dbg(" Searching for \"%s\"", name); 1348 1349 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1350 (refobj != NULL && 1351 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1352 (pathname = search_library_path(name, gethints())) != NULL || 1353 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1354 return pathname; 1355 1356 if(refobj != NULL && refobj->path != NULL) { 1357 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1358 name, basename(refobj->path)); 1359 } else { 1360 _rtld_error("Shared object \"%s\" not found", name); 1361 } 1362 return NULL; 1363 } 1364 1365 /* 1366 * Given a symbol number in a referencing object, find the corresponding 1367 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1368 * no definition was found. Returns a pointer to the Obj_Entry of the 1369 * defining object via the reference parameter DEFOBJ_OUT. 1370 */ 1371 const Elf_Sym * 1372 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1373 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1374 RtldLockState *lockstate) 1375 { 1376 const Elf_Sym *ref; 1377 const Elf_Sym *def; 1378 const Obj_Entry *defobj; 1379 SymLook req; 1380 const char *name; 1381 int res; 1382 1383 /* 1384 * If we have already found this symbol, get the information from 1385 * the cache. 1386 */ 1387 if (symnum >= refobj->nchains) 1388 return NULL; /* Bad object */ 1389 if (cache != NULL && cache[symnum].sym != NULL) { 1390 *defobj_out = cache[symnum].obj; 1391 return cache[symnum].sym; 1392 } 1393 1394 ref = refobj->symtab + symnum; 1395 name = refobj->strtab + ref->st_name; 1396 def = NULL; 1397 defobj = NULL; 1398 1399 /* 1400 * We don't have to do a full scale lookup if the symbol is local. 1401 * We know it will bind to the instance in this load module; to 1402 * which we already have a pointer (ie ref). By not doing a lookup, 1403 * we not only improve performance, but it also avoids unresolvable 1404 * symbols when local symbols are not in the hash table. This has 1405 * been seen with the ia64 toolchain. 1406 */ 1407 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1408 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1409 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1410 symnum); 1411 } 1412 symlook_init(&req, name); 1413 req.flags = flags; 1414 req.ventry = fetch_ventry(refobj, symnum); 1415 req.lockstate = lockstate; 1416 res = symlook_default(&req, refobj); 1417 if (res == 0) { 1418 def = req.sym_out; 1419 defobj = req.defobj_out; 1420 } 1421 } else { 1422 def = ref; 1423 defobj = refobj; 1424 } 1425 1426 /* 1427 * If we found no definition and the reference is weak, treat the 1428 * symbol as having the value zero. 1429 */ 1430 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1431 def = &sym_zero; 1432 defobj = obj_main; 1433 } 1434 1435 if (def != NULL) { 1436 *defobj_out = defobj; 1437 /* Record the information in the cache to avoid subsequent lookups. */ 1438 if (cache != NULL) { 1439 cache[symnum].sym = def; 1440 cache[symnum].obj = defobj; 1441 } 1442 } else { 1443 if (refobj != &obj_rtld) 1444 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1445 } 1446 return def; 1447 } 1448 1449 /* 1450 * Return the search path from the ldconfig hints file, reading it if 1451 * necessary. Returns NULL if there are problems with the hints file, 1452 * or if the search path there is empty. 1453 */ 1454 static const char * 1455 gethints(void) 1456 { 1457 static char *hints; 1458 1459 if (hints == NULL) { 1460 int fd; 1461 struct elfhints_hdr hdr; 1462 char *p; 1463 1464 /* Keep from trying again in case the hints file is bad. */ 1465 hints = ""; 1466 1467 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1468 return NULL; 1469 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1470 hdr.magic != ELFHINTS_MAGIC || 1471 hdr.version != 1) { 1472 close(fd); 1473 return NULL; 1474 } 1475 p = xmalloc(hdr.dirlistlen + 1); 1476 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1477 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1478 free(p); 1479 close(fd); 1480 return NULL; 1481 } 1482 hints = p; 1483 close(fd); 1484 } 1485 return hints[0] != '\0' ? hints : NULL; 1486 } 1487 1488 static void 1489 init_dag(Obj_Entry *root) 1490 { 1491 const Needed_Entry *needed; 1492 const Objlist_Entry *elm; 1493 DoneList donelist; 1494 1495 if (root->dag_inited) 1496 return; 1497 donelist_init(&donelist); 1498 1499 /* Root object belongs to own DAG. */ 1500 objlist_push_tail(&root->dldags, root); 1501 objlist_push_tail(&root->dagmembers, root); 1502 donelist_check(&donelist, root); 1503 1504 /* 1505 * Add dependencies of root object to DAG in breadth order 1506 * by exploiting the fact that each new object get added 1507 * to the tail of the dagmembers list. 1508 */ 1509 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1510 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1511 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1512 continue; 1513 objlist_push_tail(&needed->obj->dldags, root); 1514 objlist_push_tail(&root->dagmembers, needed->obj); 1515 } 1516 } 1517 root->dag_inited = true; 1518 } 1519 1520 /* 1521 * Initialize the dynamic linker. The argument is the address at which 1522 * the dynamic linker has been mapped into memory. The primary task of 1523 * this function is to relocate the dynamic linker. 1524 */ 1525 static void 1526 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1527 { 1528 Obj_Entry objtmp; /* Temporary rtld object */ 1529 const Elf_Dyn *dyn_rpath; 1530 const Elf_Dyn *dyn_soname; 1531 1532 /* 1533 * Conjure up an Obj_Entry structure for the dynamic linker. 1534 * 1535 * The "path" member can't be initialized yet because string constants 1536 * cannot yet be accessed. Below we will set it correctly. 1537 */ 1538 memset(&objtmp, 0, sizeof(objtmp)); 1539 objtmp.path = NULL; 1540 objtmp.rtld = true; 1541 objtmp.mapbase = mapbase; 1542 #ifdef PIC 1543 objtmp.relocbase = mapbase; 1544 #endif 1545 if (RTLD_IS_DYNAMIC()) { 1546 objtmp.dynamic = rtld_dynamic(&objtmp); 1547 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1548 assert(objtmp.needed == NULL); 1549 #if !defined(__mips__) 1550 /* MIPS has a bogus DT_TEXTREL. */ 1551 assert(!objtmp.textrel); 1552 #endif 1553 1554 /* 1555 * Temporarily put the dynamic linker entry into the object list, so 1556 * that symbols can be found. 1557 */ 1558 1559 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1560 } 1561 1562 /* Initialize the object list. */ 1563 obj_tail = &obj_list; 1564 1565 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1566 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1567 1568 if (aux_info[AT_PAGESZ] != NULL) 1569 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1570 if (aux_info[AT_OSRELDATE] != NULL) 1571 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1572 1573 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1574 1575 /* Replace the path with a dynamically allocated copy. */ 1576 obj_rtld.path = xstrdup(PATH_RTLD); 1577 1578 r_debug.r_brk = r_debug_state; 1579 r_debug.r_state = RT_CONSISTENT; 1580 } 1581 1582 /* 1583 * Add the init functions from a needed object list (and its recursive 1584 * needed objects) to "list". This is not used directly; it is a helper 1585 * function for initlist_add_objects(). The write lock must be held 1586 * when this function is called. 1587 */ 1588 static void 1589 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1590 { 1591 /* Recursively process the successor needed objects. */ 1592 if (needed->next != NULL) 1593 initlist_add_neededs(needed->next, list); 1594 1595 /* Process the current needed object. */ 1596 if (needed->obj != NULL) 1597 initlist_add_objects(needed->obj, &needed->obj->next, list); 1598 } 1599 1600 /* 1601 * Scan all of the DAGs rooted in the range of objects from "obj" to 1602 * "tail" and add their init functions to "list". This recurses over 1603 * the DAGs and ensure the proper init ordering such that each object's 1604 * needed libraries are initialized before the object itself. At the 1605 * same time, this function adds the objects to the global finalization 1606 * list "list_fini" in the opposite order. The write lock must be 1607 * held when this function is called. 1608 */ 1609 static void 1610 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1611 { 1612 1613 if (obj->init_scanned || obj->init_done) 1614 return; 1615 obj->init_scanned = true; 1616 1617 /* Recursively process the successor objects. */ 1618 if (&obj->next != tail) 1619 initlist_add_objects(obj->next, tail, list); 1620 1621 /* Recursively process the needed objects. */ 1622 if (obj->needed != NULL) 1623 initlist_add_neededs(obj->needed, list); 1624 if (obj->needed_filtees != NULL) 1625 initlist_add_neededs(obj->needed_filtees, list); 1626 if (obj->needed_aux_filtees != NULL) 1627 initlist_add_neededs(obj->needed_aux_filtees, list); 1628 1629 /* Add the object to the init list. */ 1630 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1631 obj->init_array != (Elf_Addr)NULL) 1632 objlist_push_tail(list, obj); 1633 1634 /* Add the object to the global fini list in the reverse order. */ 1635 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1636 && !obj->on_fini_list) { 1637 objlist_push_head(&list_fini, obj); 1638 obj->on_fini_list = true; 1639 } 1640 } 1641 1642 #ifndef FPTR_TARGET 1643 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1644 #endif 1645 1646 static void 1647 free_needed_filtees(Needed_Entry *n) 1648 { 1649 Needed_Entry *needed, *needed1; 1650 1651 for (needed = n; needed != NULL; needed = needed->next) { 1652 if (needed->obj != NULL) { 1653 dlclose(needed->obj); 1654 needed->obj = NULL; 1655 } 1656 } 1657 for (needed = n; needed != NULL; needed = needed1) { 1658 needed1 = needed->next; 1659 free(needed); 1660 } 1661 } 1662 1663 static void 1664 unload_filtees(Obj_Entry *obj) 1665 { 1666 1667 free_needed_filtees(obj->needed_filtees); 1668 obj->needed_filtees = NULL; 1669 free_needed_filtees(obj->needed_aux_filtees); 1670 obj->needed_aux_filtees = NULL; 1671 obj->filtees_loaded = false; 1672 } 1673 1674 static void 1675 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1676 { 1677 1678 for (; needed != NULL; needed = needed->next) { 1679 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1680 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1681 RTLD_LOCAL); 1682 } 1683 } 1684 1685 static void 1686 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1687 { 1688 1689 lock_restart_for_upgrade(lockstate); 1690 if (!obj->filtees_loaded) { 1691 load_filtee1(obj, obj->needed_filtees, flags); 1692 load_filtee1(obj, obj->needed_aux_filtees, flags); 1693 obj->filtees_loaded = true; 1694 } 1695 } 1696 1697 static int 1698 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1699 { 1700 Obj_Entry *obj1; 1701 1702 for (; needed != NULL; needed = needed->next) { 1703 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 1704 flags & ~RTLD_LO_NOLOAD); 1705 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1706 return (-1); 1707 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1708 dbg("obj %s nodelete", obj1->path); 1709 init_dag(obj1); 1710 ref_dag(obj1); 1711 obj1->ref_nodel = true; 1712 } 1713 } 1714 return (0); 1715 } 1716 1717 /* 1718 * Given a shared object, traverse its list of needed objects, and load 1719 * each of them. Returns 0 on success. Generates an error message and 1720 * returns -1 on failure. 1721 */ 1722 static int 1723 load_needed_objects(Obj_Entry *first, int flags) 1724 { 1725 Obj_Entry *obj; 1726 1727 for (obj = first; obj != NULL; obj = obj->next) { 1728 if (process_needed(obj, obj->needed, flags) == -1) 1729 return (-1); 1730 } 1731 return (0); 1732 } 1733 1734 static int 1735 load_preload_objects(void) 1736 { 1737 char *p = ld_preload; 1738 static const char delim[] = " \t:;"; 1739 1740 if (p == NULL) 1741 return 0; 1742 1743 p += strspn(p, delim); 1744 while (*p != '\0') { 1745 size_t len = strcspn(p, delim); 1746 char savech; 1747 1748 savech = p[len]; 1749 p[len] = '\0'; 1750 if (load_object(p, -1, NULL, 0) == NULL) 1751 return -1; /* XXX - cleanup */ 1752 p[len] = savech; 1753 p += len; 1754 p += strspn(p, delim); 1755 } 1756 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1757 return 0; 1758 } 1759 1760 static const char * 1761 printable_path(const char *path) 1762 { 1763 1764 return (path == NULL ? "<unknown>" : path); 1765 } 1766 1767 /* 1768 * Load a shared object into memory, if it is not already loaded. The 1769 * object may be specified by name or by user-supplied file descriptor 1770 * fd_u. In the later case, the fd_u descriptor is not closed, but its 1771 * duplicate is. 1772 * 1773 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1774 * on failure. 1775 */ 1776 static Obj_Entry * 1777 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 1778 { 1779 Obj_Entry *obj; 1780 int fd; 1781 struct stat sb; 1782 char *path; 1783 1784 if (name != NULL) { 1785 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1786 if (object_match_name(obj, name)) 1787 return (obj); 1788 } 1789 1790 path = find_library(name, refobj); 1791 if (path == NULL) 1792 return (NULL); 1793 } else 1794 path = NULL; 1795 1796 /* 1797 * If we didn't find a match by pathname, or the name is not 1798 * supplied, open the file and check again by device and inode. 1799 * This avoids false mismatches caused by multiple links or ".." 1800 * in pathnames. 1801 * 1802 * To avoid a race, we open the file and use fstat() rather than 1803 * using stat(). 1804 */ 1805 fd = -1; 1806 if (fd_u == -1) { 1807 if ((fd = open(path, O_RDONLY)) == -1) { 1808 _rtld_error("Cannot open \"%s\"", path); 1809 free(path); 1810 return (NULL); 1811 } 1812 } else { 1813 fd = dup(fd_u); 1814 if (fd == -1) { 1815 _rtld_error("Cannot dup fd"); 1816 free(path); 1817 return (NULL); 1818 } 1819 } 1820 if (fstat(fd, &sb) == -1) { 1821 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 1822 close(fd); 1823 free(path); 1824 return NULL; 1825 } 1826 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1827 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1828 break; 1829 if (obj != NULL && name != NULL) { 1830 object_add_name(obj, name); 1831 free(path); 1832 close(fd); 1833 return obj; 1834 } 1835 if (flags & RTLD_LO_NOLOAD) { 1836 free(path); 1837 close(fd); 1838 return (NULL); 1839 } 1840 1841 /* First use of this object, so we must map it in */ 1842 obj = do_load_object(fd, name, path, &sb, flags); 1843 if (obj == NULL) 1844 free(path); 1845 close(fd); 1846 1847 return obj; 1848 } 1849 1850 static Obj_Entry * 1851 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1852 int flags) 1853 { 1854 Obj_Entry *obj; 1855 struct statfs fs; 1856 1857 /* 1858 * but first, make sure that environment variables haven't been 1859 * used to circumvent the noexec flag on a filesystem. 1860 */ 1861 if (dangerous_ld_env) { 1862 if (fstatfs(fd, &fs) != 0) { 1863 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 1864 return NULL; 1865 } 1866 if (fs.f_flags & MNT_NOEXEC) { 1867 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1868 return NULL; 1869 } 1870 } 1871 dbg("loading \"%s\"", printable_path(path)); 1872 obj = map_object(fd, printable_path(path), sbp); 1873 if (obj == NULL) 1874 return NULL; 1875 1876 /* 1877 * If DT_SONAME is present in the object, digest_dynamic2 already 1878 * added it to the object names. 1879 */ 1880 if (name != NULL) 1881 object_add_name(obj, name); 1882 obj->path = path; 1883 digest_dynamic(obj, 0); 1884 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1885 RTLD_LO_DLOPEN) { 1886 dbg("refusing to load non-loadable \"%s\"", obj->path); 1887 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1888 munmap(obj->mapbase, obj->mapsize); 1889 obj_free(obj); 1890 return (NULL); 1891 } 1892 1893 *obj_tail = obj; 1894 obj_tail = &obj->next; 1895 obj_count++; 1896 obj_loads++; 1897 linkmap_add(obj); /* for GDB & dlinfo() */ 1898 max_stack_flags |= obj->stack_flags; 1899 1900 dbg(" %p .. %p: %s", obj->mapbase, 1901 obj->mapbase + obj->mapsize - 1, obj->path); 1902 if (obj->textrel) 1903 dbg(" WARNING: %s has impure text", obj->path); 1904 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1905 obj->path); 1906 1907 return obj; 1908 } 1909 1910 static Obj_Entry * 1911 obj_from_addr(const void *addr) 1912 { 1913 Obj_Entry *obj; 1914 1915 for (obj = obj_list; obj != NULL; obj = obj->next) { 1916 if (addr < (void *) obj->mapbase) 1917 continue; 1918 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1919 return obj; 1920 } 1921 return NULL; 1922 } 1923 1924 static void 1925 preinit_main(void) 1926 { 1927 Elf_Addr *preinit_addr; 1928 int index; 1929 1930 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 1931 if (preinit_addr == NULL) 1932 return; 1933 1934 for (index = 0; index < obj_main->preinit_array_num; index++) { 1935 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 1936 dbg("calling preinit function for %s at %p", obj_main->path, 1937 (void *)preinit_addr[index]); 1938 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 1939 0, 0, obj_main->path); 1940 call_init_pointer(obj_main, preinit_addr[index]); 1941 } 1942 } 1943 } 1944 1945 /* 1946 * Call the finalization functions for each of the objects in "list" 1947 * belonging to the DAG of "root" and referenced once. If NULL "root" 1948 * is specified, every finalization function will be called regardless 1949 * of the reference count and the list elements won't be freed. All of 1950 * the objects are expected to have non-NULL fini functions. 1951 */ 1952 static void 1953 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1954 { 1955 Objlist_Entry *elm; 1956 char *saved_msg; 1957 Elf_Addr *fini_addr; 1958 int index; 1959 1960 assert(root == NULL || root->refcount == 1); 1961 1962 /* 1963 * Preserve the current error message since a fini function might 1964 * call into the dynamic linker and overwrite it. 1965 */ 1966 saved_msg = errmsg_save(); 1967 do { 1968 STAILQ_FOREACH(elm, list, link) { 1969 if (root != NULL && (elm->obj->refcount != 1 || 1970 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1971 continue; 1972 /* Remove object from fini list to prevent recursive invocation. */ 1973 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1974 /* 1975 * XXX: If a dlopen() call references an object while the 1976 * fini function is in progress, we might end up trying to 1977 * unload the referenced object in dlclose() or the object 1978 * won't be unloaded although its fini function has been 1979 * called. 1980 */ 1981 lock_release(rtld_bind_lock, lockstate); 1982 1983 /* 1984 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 1985 * When this happens, DT_FINI_ARRAY is processed first. 1986 */ 1987 fini_addr = (Elf_Addr *)elm->obj->fini_array; 1988 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 1989 for (index = elm->obj->fini_array_num - 1; index >= 0; 1990 index--) { 1991 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 1992 dbg("calling fini function for %s at %p", 1993 elm->obj->path, (void *)fini_addr[index]); 1994 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 1995 (void *)fini_addr[index], 0, 0, elm->obj->path); 1996 call_initfini_pointer(elm->obj, fini_addr[index]); 1997 } 1998 } 1999 } 2000 if (elm->obj->fini != (Elf_Addr)NULL) { 2001 dbg("calling fini function for %s at %p", elm->obj->path, 2002 (void *)elm->obj->fini); 2003 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2004 0, 0, elm->obj->path); 2005 call_initfini_pointer(elm->obj, elm->obj->fini); 2006 } 2007 wlock_acquire(rtld_bind_lock, lockstate); 2008 /* No need to free anything if process is going down. */ 2009 if (root != NULL) 2010 free(elm); 2011 /* 2012 * We must restart the list traversal after every fini call 2013 * because a dlclose() call from the fini function or from 2014 * another thread might have modified the reference counts. 2015 */ 2016 break; 2017 } 2018 } while (elm != NULL); 2019 errmsg_restore(saved_msg); 2020 } 2021 2022 /* 2023 * Call the initialization functions for each of the objects in 2024 * "list". All of the objects are expected to have non-NULL init 2025 * functions. 2026 */ 2027 static void 2028 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2029 { 2030 Objlist_Entry *elm; 2031 Obj_Entry *obj; 2032 char *saved_msg; 2033 Elf_Addr *init_addr; 2034 int index; 2035 2036 /* 2037 * Clean init_scanned flag so that objects can be rechecked and 2038 * possibly initialized earlier if any of vectors called below 2039 * cause the change by using dlopen. 2040 */ 2041 for (obj = obj_list; obj != NULL; obj = obj->next) 2042 obj->init_scanned = false; 2043 2044 /* 2045 * Preserve the current error message since an init function might 2046 * call into the dynamic linker and overwrite it. 2047 */ 2048 saved_msg = errmsg_save(); 2049 STAILQ_FOREACH(elm, list, link) { 2050 if (elm->obj->init_done) /* Initialized early. */ 2051 continue; 2052 /* 2053 * Race: other thread might try to use this object before current 2054 * one completes the initilization. Not much can be done here 2055 * without better locking. 2056 */ 2057 elm->obj->init_done = true; 2058 lock_release(rtld_bind_lock, lockstate); 2059 2060 /* 2061 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2062 * When this happens, DT_INIT is processed first. 2063 */ 2064 if (elm->obj->init != (Elf_Addr)NULL) { 2065 dbg("calling init function for %s at %p", elm->obj->path, 2066 (void *)elm->obj->init); 2067 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2068 0, 0, elm->obj->path); 2069 call_initfini_pointer(elm->obj, elm->obj->init); 2070 } 2071 init_addr = (Elf_Addr *)elm->obj->init_array; 2072 if (init_addr != NULL) { 2073 for (index = 0; index < elm->obj->init_array_num; index++) { 2074 if (init_addr[index] != 0 && init_addr[index] != 1) { 2075 dbg("calling init function for %s at %p", elm->obj->path, 2076 (void *)init_addr[index]); 2077 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2078 (void *)init_addr[index], 0, 0, elm->obj->path); 2079 call_init_pointer(elm->obj, init_addr[index]); 2080 } 2081 } 2082 } 2083 wlock_acquire(rtld_bind_lock, lockstate); 2084 } 2085 errmsg_restore(saved_msg); 2086 } 2087 2088 static void 2089 objlist_clear(Objlist *list) 2090 { 2091 Objlist_Entry *elm; 2092 2093 while (!STAILQ_EMPTY(list)) { 2094 elm = STAILQ_FIRST(list); 2095 STAILQ_REMOVE_HEAD(list, link); 2096 free(elm); 2097 } 2098 } 2099 2100 static Objlist_Entry * 2101 objlist_find(Objlist *list, const Obj_Entry *obj) 2102 { 2103 Objlist_Entry *elm; 2104 2105 STAILQ_FOREACH(elm, list, link) 2106 if (elm->obj == obj) 2107 return elm; 2108 return NULL; 2109 } 2110 2111 static void 2112 objlist_init(Objlist *list) 2113 { 2114 STAILQ_INIT(list); 2115 } 2116 2117 static void 2118 objlist_push_head(Objlist *list, Obj_Entry *obj) 2119 { 2120 Objlist_Entry *elm; 2121 2122 elm = NEW(Objlist_Entry); 2123 elm->obj = obj; 2124 STAILQ_INSERT_HEAD(list, elm, link); 2125 } 2126 2127 static void 2128 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2129 { 2130 Objlist_Entry *elm; 2131 2132 elm = NEW(Objlist_Entry); 2133 elm->obj = obj; 2134 STAILQ_INSERT_TAIL(list, elm, link); 2135 } 2136 2137 static void 2138 objlist_remove(Objlist *list, Obj_Entry *obj) 2139 { 2140 Objlist_Entry *elm; 2141 2142 if ((elm = objlist_find(list, obj)) != NULL) { 2143 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2144 free(elm); 2145 } 2146 } 2147 2148 /* 2149 * Relocate newly-loaded shared objects. The argument is a pointer to 2150 * the Obj_Entry for the first such object. All objects from the first 2151 * to the end of the list of objects are relocated. Returns 0 on success, 2152 * or -1 on failure. 2153 */ 2154 static int 2155 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2156 int flags, RtldLockState *lockstate) 2157 { 2158 Obj_Entry *obj; 2159 2160 for (obj = first; obj != NULL; obj = obj->next) { 2161 if (obj->relocated) 2162 continue; 2163 obj->relocated = true; 2164 if (obj != rtldobj) 2165 dbg("relocating \"%s\"", obj->path); 2166 2167 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 2168 obj->symtab == NULL || obj->strtab == NULL) { 2169 _rtld_error("%s: Shared object has no run-time symbol table", 2170 obj->path); 2171 return -1; 2172 } 2173 2174 if (obj->textrel) { 2175 /* There are relocations to the write-protected text segment. */ 2176 if (mprotect(obj->mapbase, obj->textsize, 2177 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2178 _rtld_error("%s: Cannot write-enable text segment: %s", 2179 obj->path, rtld_strerror(errno)); 2180 return -1; 2181 } 2182 } 2183 2184 /* Process the non-PLT relocations. */ 2185 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2186 return -1; 2187 2188 if (obj->textrel) { /* Re-protected the text segment. */ 2189 if (mprotect(obj->mapbase, obj->textsize, 2190 PROT_READ|PROT_EXEC) == -1) { 2191 _rtld_error("%s: Cannot write-protect text segment: %s", 2192 obj->path, rtld_strerror(errno)); 2193 return -1; 2194 } 2195 } 2196 2197 2198 /* Set the special PLT or GOT entries. */ 2199 init_pltgot(obj); 2200 2201 /* Process the PLT relocations. */ 2202 if (reloc_plt(obj) == -1) 2203 return -1; 2204 /* Relocate the jump slots if we are doing immediate binding. */ 2205 if (obj->bind_now || bind_now) 2206 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2207 return -1; 2208 2209 if (obj->relro_size > 0) { 2210 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2211 _rtld_error("%s: Cannot enforce relro protection: %s", 2212 obj->path, rtld_strerror(errno)); 2213 return -1; 2214 } 2215 } 2216 2217 /* 2218 * Set up the magic number and version in the Obj_Entry. These 2219 * were checked in the crt1.o from the original ElfKit, so we 2220 * set them for backward compatibility. 2221 */ 2222 obj->magic = RTLD_MAGIC; 2223 obj->version = RTLD_VERSION; 2224 } 2225 2226 return (0); 2227 } 2228 2229 /* 2230 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2231 * referencing STT_GNU_IFUNC symbols is postponed till the other 2232 * relocations are done. The indirect functions specified as 2233 * ifunc are allowed to call other symbols, so we need to have 2234 * objects relocated before asking for resolution from indirects. 2235 * 2236 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2237 * instead of the usual lazy handling of PLT slots. It is 2238 * consistent with how GNU does it. 2239 */ 2240 static int 2241 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2242 RtldLockState *lockstate) 2243 { 2244 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2245 return (-1); 2246 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2247 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2248 return (-1); 2249 return (0); 2250 } 2251 2252 static int 2253 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2254 RtldLockState *lockstate) 2255 { 2256 Obj_Entry *obj; 2257 2258 for (obj = first; obj != NULL; obj = obj->next) { 2259 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2260 return (-1); 2261 } 2262 return (0); 2263 } 2264 2265 static int 2266 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2267 RtldLockState *lockstate) 2268 { 2269 Objlist_Entry *elm; 2270 2271 STAILQ_FOREACH(elm, list, link) { 2272 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2273 lockstate) == -1) 2274 return (-1); 2275 } 2276 return (0); 2277 } 2278 2279 /* 2280 * Cleanup procedure. It will be called (by the atexit mechanism) just 2281 * before the process exits. 2282 */ 2283 static void 2284 rtld_exit(void) 2285 { 2286 RtldLockState lockstate; 2287 2288 wlock_acquire(rtld_bind_lock, &lockstate); 2289 dbg("rtld_exit()"); 2290 objlist_call_fini(&list_fini, NULL, &lockstate); 2291 /* No need to remove the items from the list, since we are exiting. */ 2292 if (!libmap_disable) 2293 lm_fini(); 2294 lock_release(rtld_bind_lock, &lockstate); 2295 } 2296 2297 static void * 2298 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2299 { 2300 #ifdef COMPAT_32BIT 2301 const char *trans; 2302 #endif 2303 if (path == NULL) 2304 return (NULL); 2305 2306 path += strspn(path, ":;"); 2307 while (*path != '\0') { 2308 size_t len; 2309 char *res; 2310 2311 len = strcspn(path, ":;"); 2312 #ifdef COMPAT_32BIT 2313 trans = lm_findn(NULL, path, len); 2314 if (trans) 2315 res = callback(trans, strlen(trans), arg); 2316 else 2317 #endif 2318 res = callback(path, len, arg); 2319 2320 if (res != NULL) 2321 return (res); 2322 2323 path += len; 2324 path += strspn(path, ":;"); 2325 } 2326 2327 return (NULL); 2328 } 2329 2330 struct try_library_args { 2331 const char *name; 2332 size_t namelen; 2333 char *buffer; 2334 size_t buflen; 2335 }; 2336 2337 static void * 2338 try_library_path(const char *dir, size_t dirlen, void *param) 2339 { 2340 struct try_library_args *arg; 2341 2342 arg = param; 2343 if (*dir == '/' || trust) { 2344 char *pathname; 2345 2346 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2347 return (NULL); 2348 2349 pathname = arg->buffer; 2350 strncpy(pathname, dir, dirlen); 2351 pathname[dirlen] = '/'; 2352 strcpy(pathname + dirlen + 1, arg->name); 2353 2354 dbg(" Trying \"%s\"", pathname); 2355 if (access(pathname, F_OK) == 0) { /* We found it */ 2356 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2357 strcpy(pathname, arg->buffer); 2358 return (pathname); 2359 } 2360 } 2361 return (NULL); 2362 } 2363 2364 static char * 2365 search_library_path(const char *name, const char *path) 2366 { 2367 char *p; 2368 struct try_library_args arg; 2369 2370 if (path == NULL) 2371 return NULL; 2372 2373 arg.name = name; 2374 arg.namelen = strlen(name); 2375 arg.buffer = xmalloc(PATH_MAX); 2376 arg.buflen = PATH_MAX; 2377 2378 p = path_enumerate(path, try_library_path, &arg); 2379 2380 free(arg.buffer); 2381 2382 return (p); 2383 } 2384 2385 int 2386 dlclose(void *handle) 2387 { 2388 Obj_Entry *root; 2389 RtldLockState lockstate; 2390 2391 wlock_acquire(rtld_bind_lock, &lockstate); 2392 root = dlcheck(handle); 2393 if (root == NULL) { 2394 lock_release(rtld_bind_lock, &lockstate); 2395 return -1; 2396 } 2397 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2398 root->path); 2399 2400 /* Unreference the object and its dependencies. */ 2401 root->dl_refcount--; 2402 2403 if (root->refcount == 1) { 2404 /* 2405 * The object will be no longer referenced, so we must unload it. 2406 * First, call the fini functions. 2407 */ 2408 objlist_call_fini(&list_fini, root, &lockstate); 2409 2410 unref_dag(root); 2411 2412 /* Finish cleaning up the newly-unreferenced objects. */ 2413 GDB_STATE(RT_DELETE,&root->linkmap); 2414 unload_object(root); 2415 GDB_STATE(RT_CONSISTENT,NULL); 2416 } else 2417 unref_dag(root); 2418 2419 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2420 lock_release(rtld_bind_lock, &lockstate); 2421 return 0; 2422 } 2423 2424 char * 2425 dlerror(void) 2426 { 2427 char *msg = error_message; 2428 error_message = NULL; 2429 return msg; 2430 } 2431 2432 /* 2433 * This function is deprecated and has no effect. 2434 */ 2435 void 2436 dllockinit(void *context, 2437 void *(*lock_create)(void *context), 2438 void (*rlock_acquire)(void *lock), 2439 void (*wlock_acquire)(void *lock), 2440 void (*lock_release)(void *lock), 2441 void (*lock_destroy)(void *lock), 2442 void (*context_destroy)(void *context)) 2443 { 2444 static void *cur_context; 2445 static void (*cur_context_destroy)(void *); 2446 2447 /* Just destroy the context from the previous call, if necessary. */ 2448 if (cur_context_destroy != NULL) 2449 cur_context_destroy(cur_context); 2450 cur_context = context; 2451 cur_context_destroy = context_destroy; 2452 } 2453 2454 void * 2455 dlopen(const char *name, int mode) 2456 { 2457 2458 return (rtld_dlopen(name, -1, mode)); 2459 } 2460 2461 void * 2462 fdlopen(int fd, int mode) 2463 { 2464 2465 return (rtld_dlopen(NULL, fd, mode)); 2466 } 2467 2468 static void * 2469 rtld_dlopen(const char *name, int fd, int mode) 2470 { 2471 RtldLockState lockstate; 2472 int lo_flags; 2473 2474 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2475 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2476 if (ld_tracing != NULL) { 2477 rlock_acquire(rtld_bind_lock, &lockstate); 2478 if (sigsetjmp(lockstate.env, 0) != 0) 2479 lock_upgrade(rtld_bind_lock, &lockstate); 2480 environ = (char **)*get_program_var_addr("environ", &lockstate); 2481 lock_release(rtld_bind_lock, &lockstate); 2482 } 2483 lo_flags = RTLD_LO_DLOPEN; 2484 if (mode & RTLD_NODELETE) 2485 lo_flags |= RTLD_LO_NODELETE; 2486 if (mode & RTLD_NOLOAD) 2487 lo_flags |= RTLD_LO_NOLOAD; 2488 if (ld_tracing != NULL) 2489 lo_flags |= RTLD_LO_TRACE; 2490 2491 return (dlopen_object(name, fd, obj_main, lo_flags, 2492 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2493 } 2494 2495 static void 2496 dlopen_cleanup(Obj_Entry *obj) 2497 { 2498 2499 obj->dl_refcount--; 2500 unref_dag(obj); 2501 if (obj->refcount == 0) 2502 unload_object(obj); 2503 } 2504 2505 static Obj_Entry * 2506 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2507 int mode) 2508 { 2509 Obj_Entry **old_obj_tail; 2510 Obj_Entry *obj; 2511 Objlist initlist; 2512 RtldLockState lockstate; 2513 int result; 2514 2515 objlist_init(&initlist); 2516 2517 wlock_acquire(rtld_bind_lock, &lockstate); 2518 GDB_STATE(RT_ADD,NULL); 2519 2520 old_obj_tail = obj_tail; 2521 obj = NULL; 2522 if (name == NULL && fd == -1) { 2523 obj = obj_main; 2524 obj->refcount++; 2525 } else { 2526 obj = load_object(name, fd, refobj, lo_flags); 2527 } 2528 2529 if (obj) { 2530 obj->dl_refcount++; 2531 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2532 objlist_push_tail(&list_global, obj); 2533 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2534 assert(*old_obj_tail == obj); 2535 result = load_needed_objects(obj, 2536 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2537 init_dag(obj); 2538 ref_dag(obj); 2539 if (result != -1) 2540 result = rtld_verify_versions(&obj->dagmembers); 2541 if (result != -1 && ld_tracing) 2542 goto trace; 2543 if (result == -1 || (relocate_objects(obj, 2544 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2545 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2546 &lockstate)) == -1) { 2547 dlopen_cleanup(obj); 2548 obj = NULL; 2549 } else if (lo_flags & RTLD_LO_EARLY) { 2550 /* 2551 * Do not call the init functions for early loaded 2552 * filtees. The image is still not initialized enough 2553 * for them to work. 2554 * 2555 * Our object is found by the global object list and 2556 * will be ordered among all init calls done right 2557 * before transferring control to main. 2558 */ 2559 } else { 2560 /* Make list of init functions to call. */ 2561 initlist_add_objects(obj, &obj->next, &initlist); 2562 } 2563 } else { 2564 2565 /* 2566 * Bump the reference counts for objects on this DAG. If 2567 * this is the first dlopen() call for the object that was 2568 * already loaded as a dependency, initialize the dag 2569 * starting at it. 2570 */ 2571 init_dag(obj); 2572 ref_dag(obj); 2573 2574 if ((lo_flags & RTLD_LO_TRACE) != 0) 2575 goto trace; 2576 } 2577 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2578 obj->z_nodelete) && !obj->ref_nodel) { 2579 dbg("obj %s nodelete", obj->path); 2580 ref_dag(obj); 2581 obj->z_nodelete = obj->ref_nodel = true; 2582 } 2583 } 2584 2585 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2586 name); 2587 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2588 2589 if (!(lo_flags & RTLD_LO_EARLY)) { 2590 map_stacks_exec(&lockstate); 2591 } 2592 2593 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2594 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2595 &lockstate) == -1) { 2596 objlist_clear(&initlist); 2597 dlopen_cleanup(obj); 2598 lock_release(rtld_bind_lock, &lockstate); 2599 return (NULL); 2600 } 2601 2602 if (!(lo_flags & RTLD_LO_EARLY)) { 2603 /* Call the init functions. */ 2604 objlist_call_init(&initlist, &lockstate); 2605 } 2606 objlist_clear(&initlist); 2607 lock_release(rtld_bind_lock, &lockstate); 2608 return obj; 2609 trace: 2610 trace_loaded_objects(obj); 2611 lock_release(rtld_bind_lock, &lockstate); 2612 exit(0); 2613 } 2614 2615 static void * 2616 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2617 int flags) 2618 { 2619 DoneList donelist; 2620 const Obj_Entry *obj, *defobj; 2621 const Elf_Sym *def; 2622 SymLook req; 2623 RtldLockState lockstate; 2624 #ifndef __ia64__ 2625 tls_index ti; 2626 #endif 2627 int res; 2628 2629 def = NULL; 2630 defobj = NULL; 2631 symlook_init(&req, name); 2632 req.ventry = ve; 2633 req.flags = flags | SYMLOOK_IN_PLT; 2634 req.lockstate = &lockstate; 2635 2636 rlock_acquire(rtld_bind_lock, &lockstate); 2637 if (sigsetjmp(lockstate.env, 0) != 0) 2638 lock_upgrade(rtld_bind_lock, &lockstate); 2639 if (handle == NULL || handle == RTLD_NEXT || 2640 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2641 2642 if ((obj = obj_from_addr(retaddr)) == NULL) { 2643 _rtld_error("Cannot determine caller's shared object"); 2644 lock_release(rtld_bind_lock, &lockstate); 2645 return NULL; 2646 } 2647 if (handle == NULL) { /* Just the caller's shared object. */ 2648 res = symlook_obj(&req, obj); 2649 if (res == 0) { 2650 def = req.sym_out; 2651 defobj = req.defobj_out; 2652 } 2653 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2654 handle == RTLD_SELF) { /* ... caller included */ 2655 if (handle == RTLD_NEXT) 2656 obj = obj->next; 2657 for (; obj != NULL; obj = obj->next) { 2658 res = symlook_obj(&req, obj); 2659 if (res == 0) { 2660 if (def == NULL || 2661 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2662 def = req.sym_out; 2663 defobj = req.defobj_out; 2664 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2665 break; 2666 } 2667 } 2668 } 2669 /* 2670 * Search the dynamic linker itself, and possibly resolve the 2671 * symbol from there. This is how the application links to 2672 * dynamic linker services such as dlopen. 2673 */ 2674 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2675 res = symlook_obj(&req, &obj_rtld); 2676 if (res == 0) { 2677 def = req.sym_out; 2678 defobj = req.defobj_out; 2679 } 2680 } 2681 } else { 2682 assert(handle == RTLD_DEFAULT); 2683 res = symlook_default(&req, obj); 2684 if (res == 0) { 2685 defobj = req.defobj_out; 2686 def = req.sym_out; 2687 } 2688 } 2689 } else { 2690 if ((obj = dlcheck(handle)) == NULL) { 2691 lock_release(rtld_bind_lock, &lockstate); 2692 return NULL; 2693 } 2694 2695 donelist_init(&donelist); 2696 if (obj->mainprog) { 2697 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2698 res = symlook_global(&req, &donelist); 2699 if (res == 0) { 2700 def = req.sym_out; 2701 defobj = req.defobj_out; 2702 } 2703 /* 2704 * Search the dynamic linker itself, and possibly resolve the 2705 * symbol from there. This is how the application links to 2706 * dynamic linker services such as dlopen. 2707 */ 2708 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2709 res = symlook_obj(&req, &obj_rtld); 2710 if (res == 0) { 2711 def = req.sym_out; 2712 defobj = req.defobj_out; 2713 } 2714 } 2715 } 2716 else { 2717 /* Search the whole DAG rooted at the given object. */ 2718 res = symlook_list(&req, &obj->dagmembers, &donelist); 2719 if (res == 0) { 2720 def = req.sym_out; 2721 defobj = req.defobj_out; 2722 } 2723 } 2724 } 2725 2726 if (def != NULL) { 2727 lock_release(rtld_bind_lock, &lockstate); 2728 2729 /* 2730 * The value required by the caller is derived from the value 2731 * of the symbol. For the ia64 architecture, we need to 2732 * construct a function descriptor which the caller can use to 2733 * call the function with the right 'gp' value. For other 2734 * architectures and for non-functions, the value is simply 2735 * the relocated value of the symbol. 2736 */ 2737 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2738 return (make_function_pointer(def, defobj)); 2739 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2740 return (rtld_resolve_ifunc(defobj, def)); 2741 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 2742 #ifdef __ia64__ 2743 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 2744 #else 2745 ti.ti_module = defobj->tlsindex; 2746 ti.ti_offset = def->st_value; 2747 return (__tls_get_addr(&ti)); 2748 #endif 2749 } else 2750 return (defobj->relocbase + def->st_value); 2751 } 2752 2753 _rtld_error("Undefined symbol \"%s\"", name); 2754 lock_release(rtld_bind_lock, &lockstate); 2755 return NULL; 2756 } 2757 2758 void * 2759 dlsym(void *handle, const char *name) 2760 { 2761 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2762 SYMLOOK_DLSYM); 2763 } 2764 2765 dlfunc_t 2766 dlfunc(void *handle, const char *name) 2767 { 2768 union { 2769 void *d; 2770 dlfunc_t f; 2771 } rv; 2772 2773 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2774 SYMLOOK_DLSYM); 2775 return (rv.f); 2776 } 2777 2778 void * 2779 dlvsym(void *handle, const char *name, const char *version) 2780 { 2781 Ver_Entry ventry; 2782 2783 ventry.name = version; 2784 ventry.file = NULL; 2785 ventry.hash = elf_hash(version); 2786 ventry.flags= 0; 2787 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2788 SYMLOOK_DLSYM); 2789 } 2790 2791 int 2792 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2793 { 2794 const Obj_Entry *obj; 2795 RtldLockState lockstate; 2796 2797 rlock_acquire(rtld_bind_lock, &lockstate); 2798 obj = obj_from_addr(addr); 2799 if (obj == NULL) { 2800 _rtld_error("No shared object contains address"); 2801 lock_release(rtld_bind_lock, &lockstate); 2802 return (0); 2803 } 2804 rtld_fill_dl_phdr_info(obj, phdr_info); 2805 lock_release(rtld_bind_lock, &lockstate); 2806 return (1); 2807 } 2808 2809 int 2810 dladdr(const void *addr, Dl_info *info) 2811 { 2812 const Obj_Entry *obj; 2813 const Elf_Sym *def; 2814 void *symbol_addr; 2815 unsigned long symoffset; 2816 RtldLockState lockstate; 2817 2818 rlock_acquire(rtld_bind_lock, &lockstate); 2819 obj = obj_from_addr(addr); 2820 if (obj == NULL) { 2821 _rtld_error("No shared object contains address"); 2822 lock_release(rtld_bind_lock, &lockstate); 2823 return 0; 2824 } 2825 info->dli_fname = obj->path; 2826 info->dli_fbase = obj->mapbase; 2827 info->dli_saddr = (void *)0; 2828 info->dli_sname = NULL; 2829 2830 /* 2831 * Walk the symbol list looking for the symbol whose address is 2832 * closest to the address sent in. 2833 */ 2834 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2835 def = obj->symtab + symoffset; 2836 2837 /* 2838 * For skip the symbol if st_shndx is either SHN_UNDEF or 2839 * SHN_COMMON. 2840 */ 2841 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2842 continue; 2843 2844 /* 2845 * If the symbol is greater than the specified address, or if it 2846 * is further away from addr than the current nearest symbol, 2847 * then reject it. 2848 */ 2849 symbol_addr = obj->relocbase + def->st_value; 2850 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2851 continue; 2852 2853 /* Update our idea of the nearest symbol. */ 2854 info->dli_sname = obj->strtab + def->st_name; 2855 info->dli_saddr = symbol_addr; 2856 2857 /* Exact match? */ 2858 if (info->dli_saddr == addr) 2859 break; 2860 } 2861 lock_release(rtld_bind_lock, &lockstate); 2862 return 1; 2863 } 2864 2865 int 2866 dlinfo(void *handle, int request, void *p) 2867 { 2868 const Obj_Entry *obj; 2869 RtldLockState lockstate; 2870 int error; 2871 2872 rlock_acquire(rtld_bind_lock, &lockstate); 2873 2874 if (handle == NULL || handle == RTLD_SELF) { 2875 void *retaddr; 2876 2877 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2878 if ((obj = obj_from_addr(retaddr)) == NULL) 2879 _rtld_error("Cannot determine caller's shared object"); 2880 } else 2881 obj = dlcheck(handle); 2882 2883 if (obj == NULL) { 2884 lock_release(rtld_bind_lock, &lockstate); 2885 return (-1); 2886 } 2887 2888 error = 0; 2889 switch (request) { 2890 case RTLD_DI_LINKMAP: 2891 *((struct link_map const **)p) = &obj->linkmap; 2892 break; 2893 case RTLD_DI_ORIGIN: 2894 error = rtld_dirname(obj->path, p); 2895 break; 2896 2897 case RTLD_DI_SERINFOSIZE: 2898 case RTLD_DI_SERINFO: 2899 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2900 break; 2901 2902 default: 2903 _rtld_error("Invalid request %d passed to dlinfo()", request); 2904 error = -1; 2905 } 2906 2907 lock_release(rtld_bind_lock, &lockstate); 2908 2909 return (error); 2910 } 2911 2912 static void 2913 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2914 { 2915 2916 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2917 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2918 STAILQ_FIRST(&obj->names)->name : obj->path; 2919 phdr_info->dlpi_phdr = obj->phdr; 2920 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2921 phdr_info->dlpi_tls_modid = obj->tlsindex; 2922 phdr_info->dlpi_tls_data = obj->tlsinit; 2923 phdr_info->dlpi_adds = obj_loads; 2924 phdr_info->dlpi_subs = obj_loads - obj_count; 2925 } 2926 2927 int 2928 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2929 { 2930 struct dl_phdr_info phdr_info; 2931 const Obj_Entry *obj; 2932 RtldLockState bind_lockstate, phdr_lockstate; 2933 int error; 2934 2935 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2936 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2937 2938 error = 0; 2939 2940 for (obj = obj_list; obj != NULL; obj = obj->next) { 2941 rtld_fill_dl_phdr_info(obj, &phdr_info); 2942 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2943 break; 2944 2945 } 2946 lock_release(rtld_bind_lock, &bind_lockstate); 2947 lock_release(rtld_phdr_lock, &phdr_lockstate); 2948 2949 return (error); 2950 } 2951 2952 struct fill_search_info_args { 2953 int request; 2954 unsigned int flags; 2955 Dl_serinfo *serinfo; 2956 Dl_serpath *serpath; 2957 char *strspace; 2958 }; 2959 2960 static void * 2961 fill_search_info(const char *dir, size_t dirlen, void *param) 2962 { 2963 struct fill_search_info_args *arg; 2964 2965 arg = param; 2966 2967 if (arg->request == RTLD_DI_SERINFOSIZE) { 2968 arg->serinfo->dls_cnt ++; 2969 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2970 } else { 2971 struct dl_serpath *s_entry; 2972 2973 s_entry = arg->serpath; 2974 s_entry->dls_name = arg->strspace; 2975 s_entry->dls_flags = arg->flags; 2976 2977 strncpy(arg->strspace, dir, dirlen); 2978 arg->strspace[dirlen] = '\0'; 2979 2980 arg->strspace += dirlen + 1; 2981 arg->serpath++; 2982 } 2983 2984 return (NULL); 2985 } 2986 2987 static int 2988 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2989 { 2990 struct dl_serinfo _info; 2991 struct fill_search_info_args args; 2992 2993 args.request = RTLD_DI_SERINFOSIZE; 2994 args.serinfo = &_info; 2995 2996 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2997 _info.dls_cnt = 0; 2998 2999 path_enumerate(ld_library_path, fill_search_info, &args); 3000 path_enumerate(obj->rpath, fill_search_info, &args); 3001 path_enumerate(gethints(), fill_search_info, &args); 3002 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3003 3004 3005 if (request == RTLD_DI_SERINFOSIZE) { 3006 info->dls_size = _info.dls_size; 3007 info->dls_cnt = _info.dls_cnt; 3008 return (0); 3009 } 3010 3011 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3012 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3013 return (-1); 3014 } 3015 3016 args.request = RTLD_DI_SERINFO; 3017 args.serinfo = info; 3018 args.serpath = &info->dls_serpath[0]; 3019 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3020 3021 args.flags = LA_SER_LIBPATH; 3022 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3023 return (-1); 3024 3025 args.flags = LA_SER_RUNPATH; 3026 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3027 return (-1); 3028 3029 args.flags = LA_SER_CONFIG; 3030 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 3031 return (-1); 3032 3033 args.flags = LA_SER_DEFAULT; 3034 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3035 return (-1); 3036 return (0); 3037 } 3038 3039 static int 3040 rtld_dirname(const char *path, char *bname) 3041 { 3042 const char *endp; 3043 3044 /* Empty or NULL string gets treated as "." */ 3045 if (path == NULL || *path == '\0') { 3046 bname[0] = '.'; 3047 bname[1] = '\0'; 3048 return (0); 3049 } 3050 3051 /* Strip trailing slashes */ 3052 endp = path + strlen(path) - 1; 3053 while (endp > path && *endp == '/') 3054 endp--; 3055 3056 /* Find the start of the dir */ 3057 while (endp > path && *endp != '/') 3058 endp--; 3059 3060 /* Either the dir is "/" or there are no slashes */ 3061 if (endp == path) { 3062 bname[0] = *endp == '/' ? '/' : '.'; 3063 bname[1] = '\0'; 3064 return (0); 3065 } else { 3066 do { 3067 endp--; 3068 } while (endp > path && *endp == '/'); 3069 } 3070 3071 if (endp - path + 2 > PATH_MAX) 3072 { 3073 _rtld_error("Filename is too long: %s", path); 3074 return(-1); 3075 } 3076 3077 strncpy(bname, path, endp - path + 1); 3078 bname[endp - path + 1] = '\0'; 3079 return (0); 3080 } 3081 3082 static int 3083 rtld_dirname_abs(const char *path, char *base) 3084 { 3085 char base_rel[PATH_MAX]; 3086 3087 if (rtld_dirname(path, base) == -1) 3088 return (-1); 3089 if (base[0] == '/') 3090 return (0); 3091 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3092 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3093 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3094 return (-1); 3095 strcpy(base, base_rel); 3096 return (0); 3097 } 3098 3099 static void 3100 linkmap_add(Obj_Entry *obj) 3101 { 3102 struct link_map *l = &obj->linkmap; 3103 struct link_map *prev; 3104 3105 obj->linkmap.l_name = obj->path; 3106 obj->linkmap.l_addr = obj->mapbase; 3107 obj->linkmap.l_ld = obj->dynamic; 3108 #ifdef __mips__ 3109 /* GDB needs load offset on MIPS to use the symbols */ 3110 obj->linkmap.l_offs = obj->relocbase; 3111 #endif 3112 3113 if (r_debug.r_map == NULL) { 3114 r_debug.r_map = l; 3115 return; 3116 } 3117 3118 /* 3119 * Scan to the end of the list, but not past the entry for the 3120 * dynamic linker, which we want to keep at the very end. 3121 */ 3122 for (prev = r_debug.r_map; 3123 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3124 prev = prev->l_next) 3125 ; 3126 3127 /* Link in the new entry. */ 3128 l->l_prev = prev; 3129 l->l_next = prev->l_next; 3130 if (l->l_next != NULL) 3131 l->l_next->l_prev = l; 3132 prev->l_next = l; 3133 } 3134 3135 static void 3136 linkmap_delete(Obj_Entry *obj) 3137 { 3138 struct link_map *l = &obj->linkmap; 3139 3140 if (l->l_prev == NULL) { 3141 if ((r_debug.r_map = l->l_next) != NULL) 3142 l->l_next->l_prev = NULL; 3143 return; 3144 } 3145 3146 if ((l->l_prev->l_next = l->l_next) != NULL) 3147 l->l_next->l_prev = l->l_prev; 3148 } 3149 3150 /* 3151 * Function for the debugger to set a breakpoint on to gain control. 3152 * 3153 * The two parameters allow the debugger to easily find and determine 3154 * what the runtime loader is doing and to whom it is doing it. 3155 * 3156 * When the loadhook trap is hit (r_debug_state, set at program 3157 * initialization), the arguments can be found on the stack: 3158 * 3159 * +8 struct link_map *m 3160 * +4 struct r_debug *rd 3161 * +0 RetAddr 3162 */ 3163 void 3164 r_debug_state(struct r_debug* rd, struct link_map *m) 3165 { 3166 /* 3167 * The following is a hack to force the compiler to emit calls to 3168 * this function, even when optimizing. If the function is empty, 3169 * the compiler is not obliged to emit any code for calls to it, 3170 * even when marked __noinline. However, gdb depends on those 3171 * calls being made. 3172 */ 3173 __asm __volatile("" : : : "memory"); 3174 } 3175 3176 /* 3177 * Get address of the pointer variable in the main program. 3178 * Prefer non-weak symbol over the weak one. 3179 */ 3180 static const void ** 3181 get_program_var_addr(const char *name, RtldLockState *lockstate) 3182 { 3183 SymLook req; 3184 DoneList donelist; 3185 3186 symlook_init(&req, name); 3187 req.lockstate = lockstate; 3188 donelist_init(&donelist); 3189 if (symlook_global(&req, &donelist) != 0) 3190 return (NULL); 3191 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3192 return ((const void **)make_function_pointer(req.sym_out, 3193 req.defobj_out)); 3194 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3195 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3196 else 3197 return ((const void **)(req.defobj_out->relocbase + 3198 req.sym_out->st_value)); 3199 } 3200 3201 /* 3202 * Set a pointer variable in the main program to the given value. This 3203 * is used to set key variables such as "environ" before any of the 3204 * init functions are called. 3205 */ 3206 static void 3207 set_program_var(const char *name, const void *value) 3208 { 3209 const void **addr; 3210 3211 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3212 dbg("\"%s\": *%p <-- %p", name, addr, value); 3213 *addr = value; 3214 } 3215 } 3216 3217 /* 3218 * Search the global objects, including dependencies and main object, 3219 * for the given symbol. 3220 */ 3221 static int 3222 symlook_global(SymLook *req, DoneList *donelist) 3223 { 3224 SymLook req1; 3225 const Objlist_Entry *elm; 3226 int res; 3227 3228 symlook_init_from_req(&req1, req); 3229 3230 /* Search all objects loaded at program start up. */ 3231 if (req->defobj_out == NULL || 3232 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3233 res = symlook_list(&req1, &list_main, donelist); 3234 if (res == 0 && (req->defobj_out == NULL || 3235 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3236 req->sym_out = req1.sym_out; 3237 req->defobj_out = req1.defobj_out; 3238 assert(req->defobj_out != NULL); 3239 } 3240 } 3241 3242 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3243 STAILQ_FOREACH(elm, &list_global, link) { 3244 if (req->defobj_out != NULL && 3245 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3246 break; 3247 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3248 if (res == 0 && (req->defobj_out == NULL || 3249 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3250 req->sym_out = req1.sym_out; 3251 req->defobj_out = req1.defobj_out; 3252 assert(req->defobj_out != NULL); 3253 } 3254 } 3255 3256 return (req->sym_out != NULL ? 0 : ESRCH); 3257 } 3258 3259 /* 3260 * Given a symbol name in a referencing object, find the corresponding 3261 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3262 * no definition was found. Returns a pointer to the Obj_Entry of the 3263 * defining object via the reference parameter DEFOBJ_OUT. 3264 */ 3265 static int 3266 symlook_default(SymLook *req, const Obj_Entry *refobj) 3267 { 3268 DoneList donelist; 3269 const Objlist_Entry *elm; 3270 SymLook req1; 3271 int res; 3272 3273 donelist_init(&donelist); 3274 symlook_init_from_req(&req1, req); 3275 3276 /* Look first in the referencing object if linked symbolically. */ 3277 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3278 res = symlook_obj(&req1, refobj); 3279 if (res == 0) { 3280 req->sym_out = req1.sym_out; 3281 req->defobj_out = req1.defobj_out; 3282 assert(req->defobj_out != NULL); 3283 } 3284 } 3285 3286 symlook_global(req, &donelist); 3287 3288 /* Search all dlopened DAGs containing the referencing object. */ 3289 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3290 if (req->sym_out != NULL && 3291 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3292 break; 3293 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3294 if (res == 0 && (req->sym_out == NULL || 3295 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3296 req->sym_out = req1.sym_out; 3297 req->defobj_out = req1.defobj_out; 3298 assert(req->defobj_out != NULL); 3299 } 3300 } 3301 3302 /* 3303 * Search the dynamic linker itself, and possibly resolve the 3304 * symbol from there. This is how the application links to 3305 * dynamic linker services such as dlopen. 3306 */ 3307 if (req->sym_out == NULL || 3308 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3309 res = symlook_obj(&req1, &obj_rtld); 3310 if (res == 0) { 3311 req->sym_out = req1.sym_out; 3312 req->defobj_out = req1.defobj_out; 3313 assert(req->defobj_out != NULL); 3314 } 3315 } 3316 3317 return (req->sym_out != NULL ? 0 : ESRCH); 3318 } 3319 3320 static int 3321 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3322 { 3323 const Elf_Sym *def; 3324 const Obj_Entry *defobj; 3325 const Objlist_Entry *elm; 3326 SymLook req1; 3327 int res; 3328 3329 def = NULL; 3330 defobj = NULL; 3331 STAILQ_FOREACH(elm, objlist, link) { 3332 if (donelist_check(dlp, elm->obj)) 3333 continue; 3334 symlook_init_from_req(&req1, req); 3335 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3336 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3337 def = req1.sym_out; 3338 defobj = req1.defobj_out; 3339 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3340 break; 3341 } 3342 } 3343 } 3344 if (def != NULL) { 3345 req->sym_out = def; 3346 req->defobj_out = defobj; 3347 return (0); 3348 } 3349 return (ESRCH); 3350 } 3351 3352 /* 3353 * Search the chain of DAGS cointed to by the given Needed_Entry 3354 * for a symbol of the given name. Each DAG is scanned completely 3355 * before advancing to the next one. Returns a pointer to the symbol, 3356 * or NULL if no definition was found. 3357 */ 3358 static int 3359 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3360 { 3361 const Elf_Sym *def; 3362 const Needed_Entry *n; 3363 const Obj_Entry *defobj; 3364 SymLook req1; 3365 int res; 3366 3367 def = NULL; 3368 defobj = NULL; 3369 symlook_init_from_req(&req1, req); 3370 for (n = needed; n != NULL; n = n->next) { 3371 if (n->obj == NULL || 3372 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3373 continue; 3374 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3375 def = req1.sym_out; 3376 defobj = req1.defobj_out; 3377 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3378 break; 3379 } 3380 } 3381 if (def != NULL) { 3382 req->sym_out = def; 3383 req->defobj_out = defobj; 3384 return (0); 3385 } 3386 return (ESRCH); 3387 } 3388 3389 /* 3390 * Search the symbol table of a single shared object for a symbol of 3391 * the given name and version, if requested. Returns a pointer to the 3392 * symbol, or NULL if no definition was found. If the object is 3393 * filter, return filtered symbol from filtee. 3394 * 3395 * The symbol's hash value is passed in for efficiency reasons; that 3396 * eliminates many recomputations of the hash value. 3397 */ 3398 int 3399 symlook_obj(SymLook *req, const Obj_Entry *obj) 3400 { 3401 DoneList donelist; 3402 SymLook req1; 3403 int flags, res, mres; 3404 3405 mres = symlook_obj1(req, obj); 3406 if (mres == 0) { 3407 if (obj->needed_filtees != NULL) { 3408 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3409 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3410 donelist_init(&donelist); 3411 symlook_init_from_req(&req1, req); 3412 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3413 if (res == 0) { 3414 req->sym_out = req1.sym_out; 3415 req->defobj_out = req1.defobj_out; 3416 } 3417 return (res); 3418 } 3419 if (obj->needed_aux_filtees != NULL) { 3420 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3421 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3422 donelist_init(&donelist); 3423 symlook_init_from_req(&req1, req); 3424 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3425 if (res == 0) { 3426 req->sym_out = req1.sym_out; 3427 req->defobj_out = req1.defobj_out; 3428 return (res); 3429 } 3430 } 3431 } 3432 return (mres); 3433 } 3434 3435 static int 3436 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3437 { 3438 unsigned long symnum; 3439 const Elf_Sym *vsymp; 3440 Elf_Versym verndx; 3441 int vcount; 3442 3443 if (obj->buckets == NULL) 3444 return (ESRCH); 3445 3446 vsymp = NULL; 3447 vcount = 0; 3448 symnum = obj->buckets[req->hash % obj->nbuckets]; 3449 3450 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3451 const Elf_Sym *symp; 3452 const char *strp; 3453 3454 if (symnum >= obj->nchains) 3455 return (ESRCH); /* Bad object */ 3456 3457 symp = obj->symtab + symnum; 3458 strp = obj->strtab + symp->st_name; 3459 3460 switch (ELF_ST_TYPE(symp->st_info)) { 3461 case STT_FUNC: 3462 case STT_NOTYPE: 3463 case STT_OBJECT: 3464 case STT_GNU_IFUNC: 3465 if (symp->st_value == 0) 3466 continue; 3467 /* fallthrough */ 3468 case STT_TLS: 3469 if (symp->st_shndx != SHN_UNDEF) 3470 break; 3471 #ifndef __mips__ 3472 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3473 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3474 break; 3475 /* fallthrough */ 3476 #endif 3477 default: 3478 continue; 3479 } 3480 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3481 continue; 3482 3483 if (req->ventry == NULL) { 3484 if (obj->versyms != NULL) { 3485 verndx = VER_NDX(obj->versyms[symnum]); 3486 if (verndx > obj->vernum) { 3487 _rtld_error("%s: symbol %s references wrong version %d", 3488 obj->path, obj->strtab + symnum, verndx); 3489 continue; 3490 } 3491 /* 3492 * If we are not called from dlsym (i.e. this is a normal 3493 * relocation from unversioned binary), accept the symbol 3494 * immediately if it happens to have first version after 3495 * this shared object became versioned. Otherwise, if 3496 * symbol is versioned and not hidden, remember it. If it 3497 * is the only symbol with this name exported by the 3498 * shared object, it will be returned as a match at the 3499 * end of the function. If symbol is global (verndx < 2) 3500 * accept it unconditionally. 3501 */ 3502 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3503 verndx == VER_NDX_GIVEN) { 3504 req->sym_out = symp; 3505 req->defobj_out = obj; 3506 return (0); 3507 } 3508 else if (verndx >= VER_NDX_GIVEN) { 3509 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3510 if (vsymp == NULL) 3511 vsymp = symp; 3512 vcount ++; 3513 } 3514 continue; 3515 } 3516 } 3517 req->sym_out = symp; 3518 req->defobj_out = obj; 3519 return (0); 3520 } else { 3521 if (obj->versyms == NULL) { 3522 if (object_match_name(obj, req->ventry->name)) { 3523 _rtld_error("%s: object %s should provide version %s for " 3524 "symbol %s", obj_rtld.path, obj->path, 3525 req->ventry->name, obj->strtab + symnum); 3526 continue; 3527 } 3528 } else { 3529 verndx = VER_NDX(obj->versyms[symnum]); 3530 if (verndx > obj->vernum) { 3531 _rtld_error("%s: symbol %s references wrong version %d", 3532 obj->path, obj->strtab + symnum, verndx); 3533 continue; 3534 } 3535 if (obj->vertab[verndx].hash != req->ventry->hash || 3536 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3537 /* 3538 * Version does not match. Look if this is a global symbol 3539 * and if it is not hidden. If global symbol (verndx < 2) 3540 * is available, use it. Do not return symbol if we are 3541 * called by dlvsym, because dlvsym looks for a specific 3542 * version and default one is not what dlvsym wants. 3543 */ 3544 if ((req->flags & SYMLOOK_DLSYM) || 3545 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3546 (verndx >= VER_NDX_GIVEN)) 3547 continue; 3548 } 3549 } 3550 req->sym_out = symp; 3551 req->defobj_out = obj; 3552 return (0); 3553 } 3554 } 3555 if (vcount == 1) { 3556 req->sym_out = vsymp; 3557 req->defobj_out = obj; 3558 return (0); 3559 } 3560 return (ESRCH); 3561 } 3562 3563 static void 3564 trace_loaded_objects(Obj_Entry *obj) 3565 { 3566 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3567 int c; 3568 3569 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3570 main_local = ""; 3571 3572 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3573 fmt1 = "\t%o => %p (%x)\n"; 3574 3575 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3576 fmt2 = "\t%o (%x)\n"; 3577 3578 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3579 3580 for (; obj; obj = obj->next) { 3581 Needed_Entry *needed; 3582 char *name, *path; 3583 bool is_lib; 3584 3585 if (list_containers && obj->needed != NULL) 3586 rtld_printf("%s:\n", obj->path); 3587 for (needed = obj->needed; needed; needed = needed->next) { 3588 if (needed->obj != NULL) { 3589 if (needed->obj->traced && !list_containers) 3590 continue; 3591 needed->obj->traced = true; 3592 path = needed->obj->path; 3593 } else 3594 path = "not found"; 3595 3596 name = (char *)obj->strtab + needed->name; 3597 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3598 3599 fmt = is_lib ? fmt1 : fmt2; 3600 while ((c = *fmt++) != '\0') { 3601 switch (c) { 3602 default: 3603 rtld_putchar(c); 3604 continue; 3605 case '\\': 3606 switch (c = *fmt) { 3607 case '\0': 3608 continue; 3609 case 'n': 3610 rtld_putchar('\n'); 3611 break; 3612 case 't': 3613 rtld_putchar('\t'); 3614 break; 3615 } 3616 break; 3617 case '%': 3618 switch (c = *fmt) { 3619 case '\0': 3620 continue; 3621 case '%': 3622 default: 3623 rtld_putchar(c); 3624 break; 3625 case 'A': 3626 rtld_putstr(main_local); 3627 break; 3628 case 'a': 3629 rtld_putstr(obj_main->path); 3630 break; 3631 case 'o': 3632 rtld_putstr(name); 3633 break; 3634 #if 0 3635 case 'm': 3636 rtld_printf("%d", sodp->sod_major); 3637 break; 3638 case 'n': 3639 rtld_printf("%d", sodp->sod_minor); 3640 break; 3641 #endif 3642 case 'p': 3643 rtld_putstr(path); 3644 break; 3645 case 'x': 3646 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3647 0); 3648 break; 3649 } 3650 break; 3651 } 3652 ++fmt; 3653 } 3654 } 3655 } 3656 } 3657 3658 /* 3659 * Unload a dlopened object and its dependencies from memory and from 3660 * our data structures. It is assumed that the DAG rooted in the 3661 * object has already been unreferenced, and that the object has a 3662 * reference count of 0. 3663 */ 3664 static void 3665 unload_object(Obj_Entry *root) 3666 { 3667 Obj_Entry *obj; 3668 Obj_Entry **linkp; 3669 3670 assert(root->refcount == 0); 3671 3672 /* 3673 * Pass over the DAG removing unreferenced objects from 3674 * appropriate lists. 3675 */ 3676 unlink_object(root); 3677 3678 /* Unmap all objects that are no longer referenced. */ 3679 linkp = &obj_list->next; 3680 while ((obj = *linkp) != NULL) { 3681 if (obj->refcount == 0) { 3682 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3683 obj->path); 3684 dbg("unloading \"%s\"", obj->path); 3685 unload_filtees(root); 3686 munmap(obj->mapbase, obj->mapsize); 3687 linkmap_delete(obj); 3688 *linkp = obj->next; 3689 obj_count--; 3690 obj_free(obj); 3691 } else 3692 linkp = &obj->next; 3693 } 3694 obj_tail = linkp; 3695 } 3696 3697 static void 3698 unlink_object(Obj_Entry *root) 3699 { 3700 Objlist_Entry *elm; 3701 3702 if (root->refcount == 0) { 3703 /* Remove the object from the RTLD_GLOBAL list. */ 3704 objlist_remove(&list_global, root); 3705 3706 /* Remove the object from all objects' DAG lists. */ 3707 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3708 objlist_remove(&elm->obj->dldags, root); 3709 if (elm->obj != root) 3710 unlink_object(elm->obj); 3711 } 3712 } 3713 } 3714 3715 static void 3716 ref_dag(Obj_Entry *root) 3717 { 3718 Objlist_Entry *elm; 3719 3720 assert(root->dag_inited); 3721 STAILQ_FOREACH(elm, &root->dagmembers, link) 3722 elm->obj->refcount++; 3723 } 3724 3725 static void 3726 unref_dag(Obj_Entry *root) 3727 { 3728 Objlist_Entry *elm; 3729 3730 assert(root->dag_inited); 3731 STAILQ_FOREACH(elm, &root->dagmembers, link) 3732 elm->obj->refcount--; 3733 } 3734 3735 /* 3736 * Common code for MD __tls_get_addr(). 3737 */ 3738 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 3739 static void * 3740 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 3741 { 3742 Elf_Addr *newdtv, *dtv; 3743 RtldLockState lockstate; 3744 int to_copy; 3745 3746 dtv = *dtvp; 3747 /* Check dtv generation in case new modules have arrived */ 3748 if (dtv[0] != tls_dtv_generation) { 3749 wlock_acquire(rtld_bind_lock, &lockstate); 3750 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3751 to_copy = dtv[1]; 3752 if (to_copy > tls_max_index) 3753 to_copy = tls_max_index; 3754 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3755 newdtv[0] = tls_dtv_generation; 3756 newdtv[1] = tls_max_index; 3757 free(dtv); 3758 lock_release(rtld_bind_lock, &lockstate); 3759 dtv = *dtvp = newdtv; 3760 } 3761 3762 /* Dynamically allocate module TLS if necessary */ 3763 if (dtv[index + 1] == 0) { 3764 /* Signal safe, wlock will block out signals. */ 3765 wlock_acquire(rtld_bind_lock, &lockstate); 3766 if (!dtv[index + 1]) 3767 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3768 lock_release(rtld_bind_lock, &lockstate); 3769 } 3770 return ((void *)(dtv[index + 1] + offset)); 3771 } 3772 3773 void * 3774 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 3775 { 3776 Elf_Addr *dtv; 3777 3778 dtv = *dtvp; 3779 /* Check dtv generation in case new modules have arrived */ 3780 if (__predict_true(dtv[0] == tls_dtv_generation && 3781 dtv[index + 1] != 0)) 3782 return ((void *)(dtv[index + 1] + offset)); 3783 return (tls_get_addr_slow(dtvp, index, offset)); 3784 } 3785 3786 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 3787 3788 /* 3789 * Allocate Static TLS using the Variant I method. 3790 */ 3791 void * 3792 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3793 { 3794 Obj_Entry *obj; 3795 char *tcb; 3796 Elf_Addr **tls; 3797 Elf_Addr *dtv; 3798 Elf_Addr addr; 3799 int i; 3800 3801 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3802 return (oldtcb); 3803 3804 assert(tcbsize >= TLS_TCB_SIZE); 3805 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3806 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3807 3808 if (oldtcb != NULL) { 3809 memcpy(tls, oldtcb, tls_static_space); 3810 free(oldtcb); 3811 3812 /* Adjust the DTV. */ 3813 dtv = tls[0]; 3814 for (i = 0; i < dtv[1]; i++) { 3815 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3816 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3817 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3818 } 3819 } 3820 } else { 3821 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3822 tls[0] = dtv; 3823 dtv[0] = tls_dtv_generation; 3824 dtv[1] = tls_max_index; 3825 3826 for (obj = objs; obj; obj = obj->next) { 3827 if (obj->tlsoffset > 0) { 3828 addr = (Elf_Addr)tls + obj->tlsoffset; 3829 if (obj->tlsinitsize > 0) 3830 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3831 if (obj->tlssize > obj->tlsinitsize) 3832 memset((void*) (addr + obj->tlsinitsize), 0, 3833 obj->tlssize - obj->tlsinitsize); 3834 dtv[obj->tlsindex + 1] = addr; 3835 } 3836 } 3837 } 3838 3839 return (tcb); 3840 } 3841 3842 void 3843 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3844 { 3845 Elf_Addr *dtv; 3846 Elf_Addr tlsstart, tlsend; 3847 int dtvsize, i; 3848 3849 assert(tcbsize >= TLS_TCB_SIZE); 3850 3851 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3852 tlsend = tlsstart + tls_static_space; 3853 3854 dtv = *(Elf_Addr **)tlsstart; 3855 dtvsize = dtv[1]; 3856 for (i = 0; i < dtvsize; i++) { 3857 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3858 free((void*)dtv[i+2]); 3859 } 3860 } 3861 free(dtv); 3862 free(tcb); 3863 } 3864 3865 #endif 3866 3867 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 3868 3869 /* 3870 * Allocate Static TLS using the Variant II method. 3871 */ 3872 void * 3873 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3874 { 3875 Obj_Entry *obj; 3876 size_t size; 3877 char *tls; 3878 Elf_Addr *dtv, *olddtv; 3879 Elf_Addr segbase, oldsegbase, addr; 3880 int i; 3881 3882 size = round(tls_static_space, tcbalign); 3883 3884 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3885 tls = xcalloc(1, size + tcbsize); 3886 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3887 3888 segbase = (Elf_Addr)(tls + size); 3889 ((Elf_Addr*)segbase)[0] = segbase; 3890 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3891 3892 dtv[0] = tls_dtv_generation; 3893 dtv[1] = tls_max_index; 3894 3895 if (oldtls) { 3896 /* 3897 * Copy the static TLS block over whole. 3898 */ 3899 oldsegbase = (Elf_Addr) oldtls; 3900 memcpy((void *)(segbase - tls_static_space), 3901 (const void *)(oldsegbase - tls_static_space), 3902 tls_static_space); 3903 3904 /* 3905 * If any dynamic TLS blocks have been created tls_get_addr(), 3906 * move them over. 3907 */ 3908 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3909 for (i = 0; i < olddtv[1]; i++) { 3910 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3911 dtv[i+2] = olddtv[i+2]; 3912 olddtv[i+2] = 0; 3913 } 3914 } 3915 3916 /* 3917 * We assume that this block was the one we created with 3918 * allocate_initial_tls(). 3919 */ 3920 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3921 } else { 3922 for (obj = objs; obj; obj = obj->next) { 3923 if (obj->tlsoffset) { 3924 addr = segbase - obj->tlsoffset; 3925 memset((void*) (addr + obj->tlsinitsize), 3926 0, obj->tlssize - obj->tlsinitsize); 3927 if (obj->tlsinit) 3928 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3929 dtv[obj->tlsindex + 1] = addr; 3930 } 3931 } 3932 } 3933 3934 return (void*) segbase; 3935 } 3936 3937 void 3938 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3939 { 3940 size_t size; 3941 Elf_Addr* dtv; 3942 int dtvsize, i; 3943 Elf_Addr tlsstart, tlsend; 3944 3945 /* 3946 * Figure out the size of the initial TLS block so that we can 3947 * find stuff which ___tls_get_addr() allocated dynamically. 3948 */ 3949 size = round(tls_static_space, tcbalign); 3950 3951 dtv = ((Elf_Addr**)tls)[1]; 3952 dtvsize = dtv[1]; 3953 tlsend = (Elf_Addr) tls; 3954 tlsstart = tlsend - size; 3955 for (i = 0; i < dtvsize; i++) { 3956 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3957 free((void*) dtv[i+2]); 3958 } 3959 } 3960 3961 free((void*) tlsstart); 3962 free((void*) dtv); 3963 } 3964 3965 #endif 3966 3967 /* 3968 * Allocate TLS block for module with given index. 3969 */ 3970 void * 3971 allocate_module_tls(int index) 3972 { 3973 Obj_Entry* obj; 3974 char* p; 3975 3976 for (obj = obj_list; obj; obj = obj->next) { 3977 if (obj->tlsindex == index) 3978 break; 3979 } 3980 if (!obj) { 3981 _rtld_error("Can't find module with TLS index %d", index); 3982 die(); 3983 } 3984 3985 p = malloc(obj->tlssize); 3986 if (p == NULL) { 3987 _rtld_error("Cannot allocate TLS block for index %d", index); 3988 die(); 3989 } 3990 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3991 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3992 3993 return p; 3994 } 3995 3996 bool 3997 allocate_tls_offset(Obj_Entry *obj) 3998 { 3999 size_t off; 4000 4001 if (obj->tls_done) 4002 return true; 4003 4004 if (obj->tlssize == 0) { 4005 obj->tls_done = true; 4006 return true; 4007 } 4008 4009 if (obj->tlsindex == 1) 4010 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4011 else 4012 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4013 obj->tlssize, obj->tlsalign); 4014 4015 /* 4016 * If we have already fixed the size of the static TLS block, we 4017 * must stay within that size. When allocating the static TLS, we 4018 * leave a small amount of space spare to be used for dynamically 4019 * loading modules which use static TLS. 4020 */ 4021 if (tls_static_space) { 4022 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4023 return false; 4024 } 4025 4026 tls_last_offset = obj->tlsoffset = off; 4027 tls_last_size = obj->tlssize; 4028 obj->tls_done = true; 4029 4030 return true; 4031 } 4032 4033 void 4034 free_tls_offset(Obj_Entry *obj) 4035 { 4036 4037 /* 4038 * If we were the last thing to allocate out of the static TLS 4039 * block, we give our space back to the 'allocator'. This is a 4040 * simplistic workaround to allow libGL.so.1 to be loaded and 4041 * unloaded multiple times. 4042 */ 4043 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4044 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4045 tls_last_offset -= obj->tlssize; 4046 tls_last_size = 0; 4047 } 4048 } 4049 4050 void * 4051 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4052 { 4053 void *ret; 4054 RtldLockState lockstate; 4055 4056 wlock_acquire(rtld_bind_lock, &lockstate); 4057 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4058 lock_release(rtld_bind_lock, &lockstate); 4059 return (ret); 4060 } 4061 4062 void 4063 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4064 { 4065 RtldLockState lockstate; 4066 4067 wlock_acquire(rtld_bind_lock, &lockstate); 4068 free_tls(tcb, tcbsize, tcbalign); 4069 lock_release(rtld_bind_lock, &lockstate); 4070 } 4071 4072 static void 4073 object_add_name(Obj_Entry *obj, const char *name) 4074 { 4075 Name_Entry *entry; 4076 size_t len; 4077 4078 len = strlen(name); 4079 entry = malloc(sizeof(Name_Entry) + len); 4080 4081 if (entry != NULL) { 4082 strcpy(entry->name, name); 4083 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4084 } 4085 } 4086 4087 static int 4088 object_match_name(const Obj_Entry *obj, const char *name) 4089 { 4090 Name_Entry *entry; 4091 4092 STAILQ_FOREACH(entry, &obj->names, link) { 4093 if (strcmp(name, entry->name) == 0) 4094 return (1); 4095 } 4096 return (0); 4097 } 4098 4099 static Obj_Entry * 4100 locate_dependency(const Obj_Entry *obj, const char *name) 4101 { 4102 const Objlist_Entry *entry; 4103 const Needed_Entry *needed; 4104 4105 STAILQ_FOREACH(entry, &list_main, link) { 4106 if (object_match_name(entry->obj, name)) 4107 return entry->obj; 4108 } 4109 4110 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4111 if (strcmp(obj->strtab + needed->name, name) == 0 || 4112 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4113 /* 4114 * If there is DT_NEEDED for the name we are looking for, 4115 * we are all set. Note that object might not be found if 4116 * dependency was not loaded yet, so the function can 4117 * return NULL here. This is expected and handled 4118 * properly by the caller. 4119 */ 4120 return (needed->obj); 4121 } 4122 } 4123 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4124 obj->path, name); 4125 die(); 4126 } 4127 4128 static int 4129 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4130 const Elf_Vernaux *vna) 4131 { 4132 const Elf_Verdef *vd; 4133 const char *vername; 4134 4135 vername = refobj->strtab + vna->vna_name; 4136 vd = depobj->verdef; 4137 if (vd == NULL) { 4138 _rtld_error("%s: version %s required by %s not defined", 4139 depobj->path, vername, refobj->path); 4140 return (-1); 4141 } 4142 for (;;) { 4143 if (vd->vd_version != VER_DEF_CURRENT) { 4144 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4145 depobj->path, vd->vd_version); 4146 return (-1); 4147 } 4148 if (vna->vna_hash == vd->vd_hash) { 4149 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4150 ((char *)vd + vd->vd_aux); 4151 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4152 return (0); 4153 } 4154 if (vd->vd_next == 0) 4155 break; 4156 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4157 } 4158 if (vna->vna_flags & VER_FLG_WEAK) 4159 return (0); 4160 _rtld_error("%s: version %s required by %s not found", 4161 depobj->path, vername, refobj->path); 4162 return (-1); 4163 } 4164 4165 static int 4166 rtld_verify_object_versions(Obj_Entry *obj) 4167 { 4168 const Elf_Verneed *vn; 4169 const Elf_Verdef *vd; 4170 const Elf_Verdaux *vda; 4171 const Elf_Vernaux *vna; 4172 const Obj_Entry *depobj; 4173 int maxvernum, vernum; 4174 4175 if (obj->ver_checked) 4176 return (0); 4177 obj->ver_checked = true; 4178 4179 maxvernum = 0; 4180 /* 4181 * Walk over defined and required version records and figure out 4182 * max index used by any of them. Do very basic sanity checking 4183 * while there. 4184 */ 4185 vn = obj->verneed; 4186 while (vn != NULL) { 4187 if (vn->vn_version != VER_NEED_CURRENT) { 4188 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4189 obj->path, vn->vn_version); 4190 return (-1); 4191 } 4192 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4193 for (;;) { 4194 vernum = VER_NEED_IDX(vna->vna_other); 4195 if (vernum > maxvernum) 4196 maxvernum = vernum; 4197 if (vna->vna_next == 0) 4198 break; 4199 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4200 } 4201 if (vn->vn_next == 0) 4202 break; 4203 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4204 } 4205 4206 vd = obj->verdef; 4207 while (vd != NULL) { 4208 if (vd->vd_version != VER_DEF_CURRENT) { 4209 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4210 obj->path, vd->vd_version); 4211 return (-1); 4212 } 4213 vernum = VER_DEF_IDX(vd->vd_ndx); 4214 if (vernum > maxvernum) 4215 maxvernum = vernum; 4216 if (vd->vd_next == 0) 4217 break; 4218 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4219 } 4220 4221 if (maxvernum == 0) 4222 return (0); 4223 4224 /* 4225 * Store version information in array indexable by version index. 4226 * Verify that object version requirements are satisfied along the 4227 * way. 4228 */ 4229 obj->vernum = maxvernum + 1; 4230 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4231 4232 vd = obj->verdef; 4233 while (vd != NULL) { 4234 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4235 vernum = VER_DEF_IDX(vd->vd_ndx); 4236 assert(vernum <= maxvernum); 4237 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4238 obj->vertab[vernum].hash = vd->vd_hash; 4239 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4240 obj->vertab[vernum].file = NULL; 4241 obj->vertab[vernum].flags = 0; 4242 } 4243 if (vd->vd_next == 0) 4244 break; 4245 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4246 } 4247 4248 vn = obj->verneed; 4249 while (vn != NULL) { 4250 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4251 if (depobj == NULL) 4252 return (-1); 4253 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4254 for (;;) { 4255 if (check_object_provided_version(obj, depobj, vna)) 4256 return (-1); 4257 vernum = VER_NEED_IDX(vna->vna_other); 4258 assert(vernum <= maxvernum); 4259 obj->vertab[vernum].hash = vna->vna_hash; 4260 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4261 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4262 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4263 VER_INFO_HIDDEN : 0; 4264 if (vna->vna_next == 0) 4265 break; 4266 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4267 } 4268 if (vn->vn_next == 0) 4269 break; 4270 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4271 } 4272 return 0; 4273 } 4274 4275 static int 4276 rtld_verify_versions(const Objlist *objlist) 4277 { 4278 Objlist_Entry *entry; 4279 int rc; 4280 4281 rc = 0; 4282 STAILQ_FOREACH(entry, objlist, link) { 4283 /* 4284 * Skip dummy objects or objects that have their version requirements 4285 * already checked. 4286 */ 4287 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4288 continue; 4289 if (rtld_verify_object_versions(entry->obj) == -1) { 4290 rc = -1; 4291 if (ld_tracing == NULL) 4292 break; 4293 } 4294 } 4295 if (rc == 0 || ld_tracing != NULL) 4296 rc = rtld_verify_object_versions(&obj_rtld); 4297 return rc; 4298 } 4299 4300 const Ver_Entry * 4301 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4302 { 4303 Elf_Versym vernum; 4304 4305 if (obj->vertab) { 4306 vernum = VER_NDX(obj->versyms[symnum]); 4307 if (vernum >= obj->vernum) { 4308 _rtld_error("%s: symbol %s has wrong verneed value %d", 4309 obj->path, obj->strtab + symnum, vernum); 4310 } else if (obj->vertab[vernum].hash != 0) { 4311 return &obj->vertab[vernum]; 4312 } 4313 } 4314 return NULL; 4315 } 4316 4317 int 4318 _rtld_get_stack_prot(void) 4319 { 4320 4321 return (stack_prot); 4322 } 4323 4324 static void 4325 map_stacks_exec(RtldLockState *lockstate) 4326 { 4327 void (*thr_map_stacks_exec)(void); 4328 4329 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4330 return; 4331 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4332 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4333 if (thr_map_stacks_exec != NULL) { 4334 stack_prot |= PROT_EXEC; 4335 thr_map_stacks_exec(); 4336 } 4337 } 4338 4339 void 4340 symlook_init(SymLook *dst, const char *name) 4341 { 4342 4343 bzero(dst, sizeof(*dst)); 4344 dst->name = name; 4345 dst->hash = elf_hash(name); 4346 } 4347 4348 static void 4349 symlook_init_from_req(SymLook *dst, const SymLook *src) 4350 { 4351 4352 dst->name = src->name; 4353 dst->hash = src->hash; 4354 dst->ventry = src->ventry; 4355 dst->flags = src->flags; 4356 dst->defobj_out = NULL; 4357 dst->sym_out = NULL; 4358 dst->lockstate = src->lockstate; 4359 } 4360 4361 /* 4362 * Overrides for libc_pic-provided functions. 4363 */ 4364 4365 int 4366 __getosreldate(void) 4367 { 4368 size_t len; 4369 int oid[2]; 4370 int error, osrel; 4371 4372 if (osreldate != 0) 4373 return (osreldate); 4374 4375 oid[0] = CTL_KERN; 4376 oid[1] = KERN_OSRELDATE; 4377 osrel = 0; 4378 len = sizeof(osrel); 4379 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4380 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4381 osreldate = osrel; 4382 return (osreldate); 4383 } 4384 4385 void 4386 exit(int status) 4387 { 4388 4389 _exit(status); 4390 } 4391 4392 void (*__cleanup)(void); 4393 int __isthreaded = 0; 4394 int _thread_autoinit_dummy_decl = 1; 4395 4396 /* 4397 * No unresolved symbols for rtld. 4398 */ 4399 void 4400 __pthread_cxa_finalize(struct dl_phdr_info *a) 4401 { 4402 } 4403 4404 void 4405 __stack_chk_fail(void) 4406 { 4407 4408 _rtld_error("stack overflow detected; terminated"); 4409 die(); 4410 } 4411 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4412 4413 void 4414 __chk_fail(void) 4415 { 4416 4417 _rtld_error("buffer overflow detected; terminated"); 4418 die(); 4419 } 4420 4421 const char * 4422 rtld_strerror(int errnum) 4423 { 4424 4425 if (errnum < 0 || errnum >= sys_nerr) 4426 return ("Unknown error"); 4427 return (sys_errlist[errnum]); 4428 } 4429